4Way 3Position Directional Valve (2P)
Libraries:
Simscape /
Fluids /
TwoPhase Fluid /
Valves & Orifices /
Directional Control Valves
Description
The 4Way 3Position Directional Valve (2P) block models a valve with four openings in a twophase fluid network, typically between an actuator, pump, and tank. A single spool controls the valve operation according to the signal at port S. You can set the baseline configuration of your valve by specifying the orifices that are open when the spool is in the neutral position (centered at 0 m) in the Neutral spool position open connections parameter, when the spool moves in the positive direction in the Positive spool position open connections parameter, and when the spool moves in the negative direction in the Negative spool position open connections parameter. You can use the Orifice parameterization parameter to specify the valve model as a linear relationship or function of userprovided data.
This block is a composite component that comprises of multiple instances of the Orifice (2P) block. For more information about the valve parameterizations and block calculations, see the Orifice (2P) block.
In this example configuration, the Neutral spool position open
connections parameter is All closed
. When the
spool is in the neutral position, all orifices are closed to flow:
In this configuration, Negative spool position open connections is
PA, BT
. When the signal at port S
moves the spool to a negative position, the paths between ports P
and A and between ports B and
T are open to flow. The paths between ports
P and B and ports A
and T are closed to flow:
In this configuration, Positive spool position open connections is
PB, AT
. When the signal at port S
moves the spool to a positive position, the paths between ports P
and B and between ports A and
T are open to flow and the paths between ports
P and A and between ports
B and T are closed:
This schematic shows this configuration:
The left side corresponds to the positive position and the right side corresponds to the negative position.
Spool Displacement and Valve Configuration
The spool stroke is the amount of spool travel an orifice takes to fully open from a closed position. You can define the spool stroke using the parameters in the Valve Configuration section. The table shows how the block calculates the stroke in accordance with the valve orifice parameterization and flow path characteristics.
The direction of spool movement specified by port S depends on the spool stroke and the orifice orientation.
Spool Position When Orifice Is Open  Spool Travel, ΔS 

Always closed (orifice is not selected in any spool position configuration)  N/A 
Always open (orifice is selected in positive, neutral, and negative spool position configurations)  N/A 
Negative  S_{orifice_max} + spool stroke – S 
Negative and Neutral  S_{orifice_max} + spool stroke – S 
Positive  S_{orifice_max} – spool stroke + S 
Positive and Neutral  S_{orifice_max} – spool stroke + S 
Neutral  S_{orifice_max} + spool stroke – S 
Positive and Negative  –S_{orifice_max} + spool stroke – S 
S_{orifice_max} is the spool position at the maximum orifice area defined for each orifice. The orifice area saturates at the leakage area when ΔS is negative and saturates at the maximum orifice area when the orifice is fully open. When the orifice is fully open, ΔS is equal to the spool stroke, so a value of ΔS that is greater than the spool stroke does not further increase the orifice area.
The Consistency check for neutral spool position open connections parameter verifies that:
Any orifice listed in Neutral spool position open connections is open when the signal at S is 0
Any orifice that is not listed in Neutral spool position open connections is closed when the signal at S is 0
You can optionally choose to receive a warning or error when any spool positions violate this check.
This table shows the possible configurations of the 4Way 3Position Directional Valve (TL) block.
Configuration  Parameter Values 

All four orifices are closed in the neutral position.
 
All four orifices are open in the neutral position.
 
Orifices AT and BT are closed. Orifices PA and PB are overlapped.
 
Orifices AT and BT are open. Orifices PA and PB are overlapped.
 
Orifices PA and AT are open in the neutral position. Orifices PB and BT are overlapped.
 
Orifice AT is open in the neutral position. Orifices PB, AT, and BT are overlapped.
 
Orifice BT is open in the neutral position. Orifices PA, PB, and AT are overlapped.
 
Orifices PA and PB are open. Orifices AT and BT are overlapped.
 
Orifice PA is open in the neutral position. Orifices PB, AT, and BT are overlapped.
 
Orifice PB is open in the neutral position. Orifices PA, AT, and BT are overlapped.
 
Orifices PB and BT are open in the neutral position. Orifices PA and AT are overlapped.
 
Orifices PA, PB, AT, and BT are closed in the neutral position. PT is open in the neutral position and closes when the spool displaces.
 
Orifice PA is a constant orifice. Orifices PB, AT, and BT are open in the neutral position.
 
Orifice PB is a constant orifice. Orifices PA, AT, BT are open in the neutral position.
 
Orifice PA is closed in the neutral position. Ports A and T do not form a flow path.
 
Orifice PB is closed in the neutral position. Ports B and T do not form a flow path.
 
Orifice PA is closed in the neutral position. Orifice AT is open in the neutral position.
 
Orifice PB is closed in the neutral position. Orifice BT is open in the neutral position.
 
Orifice PB is closed in the neutral position. Orifice PT is open in the neutral position. Ports A and T do not form a flow path.
 
Orifice PA is closed in the neutral position. Orifice PT is open in the neutral position. Ports A and T do not form a flow path.

Valve Orifice Parameterizations
The Modeling option parameter controls the parameterization options for a valve that models either vapor or liquid, but does not impact the fluid properties. The block calculates the fluid properties inside the valve from the inlet conditions.
The Orifice parameterization parameter specifies the model
for the open area or flow rate through one or all of the valve orifices. If you set
Area characteristics to Identical for all flow
paths
, the block applies the same data for all flow paths. When
you select Different for all flow paths
, the block uses
individual parameterizations for each flow path.
When Modeling option is Liquid operating
condition
, the block parameterization model a valve that
controls liquid flow.
When Orifice parameterization is Linear 
Area vs. spool travel
, the opening area is a linear function
of the spool position received as a signal at port S
$${A}_{orifice}=\frac{\left({A}_{\mathrm{max}}{A}_{leak}\right)}{\Delta {S}_{\mathrm{max}}}\Delta S+{A}_{leak},$$
where:
ΔS is the spool travel.
A_{orifice} saturates at A_{leak} when ΔS is negative and saturates at A_{max} when the orifice is fully open. When the orifice is fully open, ΔS is equal to the spool stroke, so a value of ΔS that is greater than the spool stroke does not increase the orifice area.
ΔS_{max} is the value of the Spool travel between closed and open orifice parameter.
A_{max} is the value of the Maximum orifice area parameter.
A_{leak} is the value of the Leakage area parameter.
When the valve is in a nearopen or nearclosed position in the linear parameterization, you can maintain numerical robustness in your simulation by adjusting the Smoothing factor parameter. If the Smoothing factor parameter is nonzero, the block smoothly saturates the opening area between A_{leak} and A_{max}. For more information, see Numerical Smoothing.
When Orifice parameterization is Tabulated data  Area
vs. spool travel
, you can provide spool travel vectors for
your system or for individual flow paths between ports P,
A, B, and T.
The block uses this data to calculate the relationship between the orifice area
and spool displacement. The block uses interpolation to determine the opening
area between given data points. A_{leak}
and A_{max} are the first and last
parameters of the opening area vector, respectively.
When Orifice parameterization is Tabulated data 
Nominal mass flow rate vs. spool travel
, the block calculates
the mass flow rate for each orifice from the nominal conditions you specify in
the block parameters. The spool position signal from port S
scales the orifice opening area, which can also scale mass flow rate.
When Modeling option is Vapor operating
condition
, the block parameterizations are designed to model a
valve that controls vapor flow.
The method the block uses to control each orifice depends on the Opening characteristic parameter:
Linear
— The measure of flow capacity depends on the spool position at port S. As the spool displaces to open to orifice, the measure of flow capacity scales from the specified minimum to the specified maximum.Tabulated
— The block calculates the measure of flow capacity as a function of the spool position at port S. This function uses a onedimensional lookup table.
The Orifice parameterization parameter determines how the block calculates the flow rate in each orifice:
Cv flow coefficient
— The flow coefficient C_{v} scales the flow rate in each orifice. The flow coefficient measures the ease with which a fluid can flow when driven by a certain pressure differential.Kv flow coefficient
— The flow coefficient K_{v}, where $${K}_{v}=0.865{C}_{v}$$, scales the flow rate in each orifice. The flow coefficient measures the ease with which a fluid can flow when driven by a certain pressure differential.Orifice area
— The size of the orifice area scales the flow rate in each orifice.
Visualize Orifice Openings
To visualize the spool offsets and maximum displacement, rightclick the block and select Fluids > Plot Valve Characteristics. The plot shows the orifices selected in the Valve Configuration settings. The orifice parameterization sets the axes, which are either:
Orifice area versus spool position
Volumetric flow rate versus spool position, queried at a specific pressure differential
Mass flow rate versus spool position for the reference inflow temperature and reference inflow pressure, queried at a specific pressure differential
When the positive, neutral, and negative settings in the Valve Configuration parameters feature the same orifice, the plot displays the orifice openings as a constant.
To update the data after changing the block parameters, click Reload Data on the figure window.
This image shows an example valve configuration. In the Valve Configuration settings:
Positive spool position open connections is
PA, BT
Neutral spool position open connections is
PT
Negative spool position open connections is
PB, AT
In the PA Orifice settings:
Spool position at maximum PA orifice area is
2.5e3 m
All other spool positions are at the default values.
The visualization shows that the PA orifice is open between the spool position at
2.53e3
and 2.53e3
m. Because the PA
orifice is open only when the spool is displaced in the positive direction, setting
the Consistency check for neutral spool and position open
connections parameter to Warning
returns:
Warning: PA orifice must be closed when the spool is in
the neutral position. Adjust Spool position at maximum PA orifice area, Neutral
spool position open connections, or Consistency check for neutral spool position
open connections. Rightclick on the block and select Fluids > Plot Valve
Characteristics to view the area or flow of each connection versus spool
position.
To resolve this warning, you can change:
Spool position at maximum PA orifice area to a value larger than 0.005 m
Consistency check for neutral spool position open connections to
None
The valve configuration by setting Neutral spool position open connections to
PA
Assumptions and Limitations
There is no heat exchange between the valve and the environment.
When Modeling option is
Liquid operating condition
, the results may not be accurate outside of the subcooled liquid region. When Modeling option isVapor operating condition
, the results may not be accurate outside of the superheated vapor region. To model a valve in a liquidvapor mixture, set Modeling option toLiquid operating condition
.
Ports
Conserving
A — Entry or exit port
twophase fluid
Twophase fluid conserving port associated with the entry or exit port to the valve.
B — Entry or exit port
twophase fluid
Twophase fluid conserving port associated with the entry or exit port to the valve.
P — Entry or exit port
twophase fluid
Twophase fluid conserving port associated with the entry or exit port to the valve.
T — Entry or exit port
twophase fluid
Twophase fluid conserving port associated with the entry or exit port to the valve.
Input
S — Spool displacement, m
physical signal
Physical signal associated with the spool displacement, in m.
Parameters
Modeling option — Modeling option for fluid phase
Liquid operating
condition
(default)  Vapor operating condition
Modeling option for the fluid phase at the valve. Set this parameter to
Liquid operating condition
if the twophase
fluid at the block location is in a liquid state. Set this parameter to
Vapor operating condition
if the twophase
fluid at the block location is in a vapor state.
Valve Configuration
Positive spool position open connections — Flow paths open when the spool is in positive position
PA, BT
(default)  PA, PB
 PB, AT
 PA
 PB
 PA, PB, AB
Flow paths open when the spool is in a positive position. This
parameter sets the valve configuration and defines the direction of
spool movement according to the signal received at port
S. To check the parameter settings for
consistency with other orifices, set Consistency check for
neutral spool position open connections to
Warning
or
Error
.
Neutral spool position open connections — Flow paths open when spool is in neutral position
All closed
(default)  PA, PB, AT, BT
 AT, BT
 PA, AT
 PA, BT
 PA, PB
 PB, AT
 PB, BT
 AT
 BT
 PA
 PB
 PT
 PA, AT, PT
 PA, PB, AB
 PB, BT, PT
 PA, PB, AT, BT, PT
Flow paths open when the spool is in the neutral position. This
parameter sets the valve configuration and defines the direction of
spool movement according to the signal received at port
S. To check the parameter settings for
consistency with other orifices, set Consistency check for
neutral spool position open connections to
Warning
or
Error
.
Negative spool position open connections — Flow paths open when spool moves in negative direction
PA, BT
(default)  PA, PB
 PB, AT
 PA
 PB
 PA, PB, AB
Flow paths open when the spool moves in the negative direction. This
parameter sets the valve configuration and defines the direction of
spool movement according to the signal received at port
S. To check the parameter settings for
consistency with other orifices, set Consistency check for
neutral spool position open connections to
Warning
or
Error
.
Consistency check for neutral spool position open connections — Whether to check if orifice settings are consistent
Warning
(default)  Error
 None
Whether to check if the neutral spool position open settings in the Valve Configuration section are consistent with the specified spool position at the maximum orifice area. For each enabled orifice, the actual offset at the spool neutral position should be commensurate with the specified spool offset for each individual orifice.
Model Parameterization
Area characteristics — Flow equations for orifices
Identical for all flow
paths
(default)  Different for each flow path
Whether to apply uniform or individual flow equations for the valve
orifice area. When you set this parameter to Identical for
all flow paths
, the block uses the same orifice and
spool geometries, flow rates, pressure, and area vectors for all valve
orifices. When you set this parameter to Different for each
flow path
, you can specify these parameters
individually for each orifice. For both settings, orifices
A, B,
P, and T have the same
crosssectional areas, discharge coefficients, and Reynolds numbers when
you set Orifice parameterization to
Linear  Area vs. spool travel
or
Tabulated data  Area vs. spool travel
.
Orifice parameterization — Variable or constant orifice parameterization
Linear  Area vs. spool
travel
(default)  Linear  Nominal mass flow rate vs. spool
travel
 Tabulated data  Area vs. spool
travel
 Cv flow coefficient
 Kv flow coefficient
 Orifice area
Method the block uses to calculate the mass flow rate from the pressure difference across the orifice or the pressure difference from the mass flow rate.
When Modeling option is Liquid
operating condition
, the choices for this parameter are:
Linear  Area vs. spool travel
Linear  Nominal mass flow rate vs. spool travel
Tabulated data  Area vs. spool travel
When Modeling option is Vapor
operating condition
, the choices for this parameter are:
Cv flow coefficient
Kv flow coefficient
Orifice area
Spool travel between closed and open orifice — Maximum spool stroke
0.005 m
(default)  positive scalar
Maximum distance of spool travel.
Dependencies
To enable this parameter, set Area
characteristics to Identical for all
flow paths
and either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
and Opening characteristic toLinear
.
Maximum orifice area — Maximum orifice opening area
1e4 m^2
(default)  positive scalar
Largest open area of each orifice during the operation of the valve.
Dependencies
To enable this parameter, set Area
characteristics to Identical for all
flow paths
and either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toLinear
.
Nominal mass flow rate at maximum orifice opening — Rated mass flow rate
0.1
kg/s (default)  positive scalar
Typical, rated, or design mass flow rate at the orifice maximum opening position.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
, and
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
.
Nominal pressure drop at maximum orifice opening — Rated pressure drop
0.001
MPa (default)  positive scalar
Typical, rated, or design pressure drop at the orifice maximum opening position.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
, and
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
.
Nominal inlet condition specification — Method of determining inlet fluid state
Temperature
(default)  Vapor quality
 Vapor void fraction
 Specific enthalpy
 Specific internal energy
Method of determining the inlet fluid state. The block determines the orifice nominal inlet specific volume from the tabulated fluid properties data based on the value of the Nominal inlet pressure and Nominal inlet condition specification parameters.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
, and
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
.
Nominal inlet pressure — Inlet fluid pressure
0.101325
MPa (default)  positive scalar
Inlet pressure in nominal conditions. The block determines the inlet specific volume from the tabulated fluid properties data based on the value of the Nominal inlet pressure and Nominal inlet condition specification parameters.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
, and
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
.
Nominal inlet temperature — Fluid temperature
293.15
K (default)  positive scalar
Inlet fluid temperature in nominal operating conditions.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
, and Nominal inlet condition
specification to
Temperature
.
Nominal inlet vapor quality — Inlet vapor quality mass fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor quality by mass fraction in nominal operating
conditions. A value of 0
means that the inlet fluid
is subcooled liquid. A value of 1
means that the
inlet fluid is superheated vapor.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
, and Nominal inlet condition
specification to Vapor
quality
.
Nominal inlet vapor void fraction — Inlet volume fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture volume fraction in nominal operating conditions. A value
of 0
means that the inlet fluid is subcooled liquid.
A value of 1
means that the inlet fluid is
superheated vapor.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
, and Nominal inlet condition
specification to Vapor void
fraction
.
Nominal inlet specific enthalpy — Inlet fluid specific enthalpy
400
kJ/kg (default)  positive scalar
Inlet specific enthalpy in nominal operating conditions.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
, and Nominal inlet condition
specification to Specific
enthalpy
.
Nominal inlet specific internal energy — Inlet specific internal energy
400
kJ/kg (default)  positive scalar
Inlet specific internal energy in nominal operating conditions.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool
travel
, and Nominal inlet condition
specification to Specific internal
energy
.
Opening characteristic — Method to convert control signal to measure of flow capacity
Linear
(default)  Tabulated
Method by which to convert the control signal specified at port S to the chosen measure of flow capacity.
Dependencies
To enable this parameter, set Modeling option
to Vapor operating condition
.
Spool travel vector — Vector of spool opening distances relative to fully closed position
[0, .00125, .0025, .00375, .005]
m
(default)  1byn vector
Vector of spool travel distances when parameterizing the orifice according to the tabulated valve area data. The vector elements must correspond onetoone with the elements in the Orifice area vector parameter. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.
Dependencies
To enable this parameter, set Area
characteristics to Identical for all
flow paths
and either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
and Opening characteristic toTabulated
.
Orifice area vector — Vector of valve opening areas
[1e10, 1e05, 4e05, 6e05, .0001]
m^2
(default)  1byn vector
Vector of opening areas when parameterizing the orifice according to the tabulated valve area data. The vector elements must correspond onetoone with the elements in the Spool travel vector parameter. List the values in ascending order. The elements must be greater than 0.
Dependencies
To enable this parameter, set Area
characteristics to Identical for all
flow paths
and either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toTabulated
.
Maximum Cv flow coefficient — C_{v} coefficient that corresponds to maximally open component
4
(default)  positive scalar
Value of the C_{v} flow coefficient when the orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set Modeling option
to Vapor operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to Cv
flow coefficient
, and Opening
characteristic to
Linear
.
Cv flow coefficient vector — C_{v} coefficients for values in member position vector
[1e06, .8, 1.6, 2.4, 3.2, 4]
(default)  1byn vector
Vector of C_{v} flow coefficients. Each coefficient corresponds to a value in the Control member position vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the Control member position vector parameter.
Dependencies
To enable this parameter, set Modeling option
to Vapor operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to Cv
flow coefficient
, and Opening
characteristic to
Tabulated
.
Maximum Kv flow coefficient — K_{v} coefficient that corresponds to maximally open component
3.6
(default)  positive scalar
Value of the K_{v} flow coefficient when the orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set Modeling option
to Vapor operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to Kv
flow coefficient
, and Opening
characteristic to
Linear
.
Kv flow coefficient vector — K_{v} coefficients for values in member position vector
[1e06, .72, 1.44, 2.16, 2.88, 3.6]
(default)  1byn vector
Vector of K_{v} flow coefficients. Each coefficient corresponds to a value in the Control member position vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the Control member position vector parameter.
Dependencies
To enable this parameter, set Modeling option
to Vapor operating condition
,
Area characteristics to
Identical for all flow paths
,
Orifice parameterization to Kv
flow coefficient
, and Opening
characteristic to
Tabulated
.
xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
0.7
(default)  positive scalar
Ratio between the inlet pressure, p_{in}, and the outlet pressure, p_{out}, defined as $$({p}_{in}{p}_{out})/{p}_{in}$$ where choking first occurs.
Dependencies
To enable this parameter, Modeling option to
Vapor operating condition
,
Area characteristics to
Identical for all flow paths
, and
Orifice parameterization to Cv
flow coefficient
or Kv flow
coefficient
.
Discharge coefficient — Discharge coefficient
0.64
(default)  positive scalar
Correction factor that accounts for discharge losses in theoretical flows.
Dependencies
To enable this parameter, set Modeling option
to Vapor operating condition
and
Orifice parameterization to
Orifice area
or set
Modeling option to Liquid
operating condition
and Orifice
parameterization to either:
Linear  Area vs. spool travel
Tabulated data  Area vs. spool travel
Leakage flow fraction — Ratio of flow rates
1e6
(default)  positive scalar
Ratio of the flow rate of the orifice when it is closed to when it is open.
Dependencies
To enable this parameter, set either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
and Opening characteristic toLinear
.
Smoothing factor — Numerical smoothing factor
0.01
(default)  positive scalar in the range of [0,1]
Continuous smoothing factor that introduces a layer of gradual change based on the flow response when the valve is in the nearopen and nearclosed positions. To increase the stability of your simulation in these regimes, set this parameter to a nonzero value less than one.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
and
Orifice parametrization to
Linear  area vs. spool travel
or set
Modeling option to Vapor
operating condition
and Opening
characteristic to
Linear
.
Pressure recovery — Whether to account for pressure increase in area expansions
off
(default)  on
Whether to account for pressure increase when fluid flows from a region of smaller crosssectional area to a region of larger crosssectional area.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
and
Orifice parameterization to either:
Linear  area vs. spool travel
Tabulated data  Area vs. spool travel
Laminar flow pressure ratio — Laminarturbulent transition pressure ratio
0.999
(default)  positive scalar
Ratio of the orifice outlet pressure to orifice inlet pressure at which the fluid transitions between the laminar and turbulent regimes. The pressure loss corresponds to the mass flow rate linearly in laminar flows and quadratically in turbulent flows.
Inlet phase change time constant — Time lag for mixture specific volume
0.1
s
(default)  positive scalar
Time lag for liquidvapor mixtures when computing the fluid specific volume. This parameter does not influence the specific volume when the inlet fluid is a fully supercooled liquid or fully superheated vapor.
Dependencies
To enable this parameter, set Modeling option
to Liquid operating condition
.
Crosssectional area at ports P, T, A and B — Area at conserving ports
0.01 m^2
(default)  positive scalar
Maximum crosssectional areas at the entry and exit ports P, T, A, and B, which the block uses in the pressureflow rate equation that determines the mass flow rate through the valve.
PA Orifice
Spool position at maximum PA orifice area — Spool offset for fully open PA orifice
5e3 m
(default)  positive scalar
Spool offset from the neutral position for a fully open PA orifice.
Dependencies
To enable this parameter, set one of these parameters.
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
Note:
This parameter is enabled only when the PA orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PA spool travel between closed and open orifice — Maximum spool stroke
0.005 m
(default)  positive scalar
Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toLinear  Area vs. spool travel
orLinear  Nominal mass flow rate vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toLinear
.
PA nominal mass flow rate at maximum orifice opening — Rated mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a maximally open PA orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal pressure drop at maximum orifice opening — Rated pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a maximally open PA orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal inlet condition specification — Method of determining inlet fluid state
Temperature
(default)  Vapor quality
 Vapor void fraction
 Specific enthalpy
 Specific internal energy
Method of determining the inlet fluid state for PA orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal inlet pressure — Inlet fluid pressure
0.101325
MPa
(default)  positive scalar
Inlet pressure for the PA orifice at nominal conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal inlet temperature — Fluid temperature
293.15
K
(default)  positive scalar
Inlet fluid temperature for the PA orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Temperature
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal inlet vapor quality — Inlet vapor quality mass fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor quality by mass fraction for the PA orifice in nominal operating
conditions. A value of 0
means that the inlet fluid
is subcooled liquid. A value of 1
means that the
inlet fluid is superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor quality
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal inlet vapor void fraction — Inlet vapor void fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor void fraction for the PA orifice in nominal operating conditions. A
value of 0
means that the inlet fluid is subcooled
liquid. A value of 1
means that the inlet fluid is
superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor void fraction
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal inlet specific enthalpy — Inlet fluid specific enthalpy
400
kJ/kg
(default)  positive scalar
Inlet specific enthalpy for the PA orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific enthalpy
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA nominal inlet specific internal energy — Inlet specific internal energy
400
kJ/kg
(default)  positive scalar
Inlet specific internal energy for the PA orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific internal energy
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA constant orifice nominal mass flow rate — Nominal mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a constant PA orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
Note:
This parameter is enabled only when the PA orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PA constant orifice nominal pressure drop — Nominal pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a constant PA orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
Note:
This parameter is enabled only when the PA orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PA constant orifice Cv flow coefficient — Flow coefficient
4
(default)  positive scalar
Value of the constant C_{v} flow coefficient for the PA orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
Note:
This parameter is enabled only when the PA orifice settings appear all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PA orifice maximum Cv flow coefficient — C_{v} coefficient that corresponds to maximally open component
4
(default)  positive scalar
Value of the C_{v} flow coefficient when the PA orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA orifice Cv flow coefficient vector — C_{v} coefficients for values in member position vector
[1e06, .8, 1.6, 2.4, 3.2, 4]
(default)  1byn vector
Vector of C_{v} flow coefficients. Each coefficient corresponds to a value in the PA orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the PA orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA constant orifice Kv flow coefficient — Flow coefficient
3.6
(default)  positive scalar
Value of the constant K_{v} flow coefficient for the PA orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
Note:
This parameter is enabled only when the PA orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PA orifice maximum Kv flow coefficient — K_{v} coefficient that corresponds to maximally open component
3.6
(default)  positive scalar
Value of the K_{v} flow coefficient when the PA orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA orifice Kv flow coefficient vector — K_{v} coefficients for values in member position vector
[1e06, .72, 1.44, 2.16, 2.88, 3.6]
(default)  1byn vector
Vector of K_{v} flow coefficients. Each coefficient corresponds to a value in the PA orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the PA orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PA orifice spool travel vector — Vector of spool opening distances relative to fully closed position
[0, .00125, .0025, .00375, .005]
m
(default)  1byn vector
Vector of spool travel distances for the tabular parameterization of the valve area. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
PA maximum orifice area — Maximum orifice opening area
1e4 m^2
(default)  positive scalar
Largest open area of the PA orifice during the operation of the valve.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toLinear
.
PA orifice area vector — Vector of valve opening areas
[1e10, 1e05, 4e05, 6e05, .0001]
m^2
(default)  1byn vector
Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond onetoone with the elements in the PA orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toTabulated
.
PA constant orifice area — Crosssectional area for constant orifice
1e4 m^2
(default)  positive scalar
Orifice area when the positive and negative spool positions include the same orifice.
Dependencies
To enable this parameter, set one of the following settings in each parameter:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
orLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
Note:
This parameter is enabled only when the PA orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PA orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
0.7
(default)  positive scalar
Ratio between the inlet pressure, p_{in}, and the outlet pressure, p_{out}, defined as $$({p}_{in}{p}_{out})/{p}_{in}$$ where choking first occurs for the PA orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
orCv flow coefficient
At least one of the following parameters:
Positive spool position open connections to:
PA, BT
PA, PB
PA
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, AT, PT
PA, PB, AB
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PA, AT
PA, BT
PA, PB
PA
PA, PB, AB
PB Orifice
Spool position at maximum PB orifice area — Spool offset for fully open PB orifice
5e3 m
(default)  positive scalar
Spool offset from the neutral position for a fully open PB orifice.
Dependencies
To enable this parameter, set one of these parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
Note:
This parameter is enabled only when the PB orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PB spool travel between closed and open orifice — Maximum spool stroke
0.005 m
(default)  positive scalar
Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toLinear  Area vs. spool travel
orLinear  Nominal mass flow rate vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toLinear
.
PB nominal mass flow rate at maximum orifice opening — Rated mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a maximally open PB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal pressure drop at maximum orifice opening — Rated pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a maximally open PB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal inlet condition specification — Method of determining inlet fluid state
Temperature
(default)  Vapor quality
 Vapor void fraction
 Specific enthalpy
 Specific internal energy
Method of determining the inlet fluid state for PB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal inlet pressure — Inlet fluid pressure
0.101325
MPa
(default)  positive scalar
Inlet pressure for the PB orifice at nominal conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal inlet temperature — Fluid temperature
293.15
K
(default)  positive scalar
Inlet fluid temperature for the PB orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Temperature
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal inlet vapor quality — Inlet vapor quality mass fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor quality by mass fraction for the PB orifice in nominal operating
conditions. A value of 0
means that the inlet fluid
is subcooled liquid. A value of 1
means that the
inlet fluid is superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor quality
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal inlet vapor void fraction — Inlet vapor void fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor void fraction for the PB orifice in nominal operating conditions. A
value of 0
means that the inlet fluid is subcooled
liquid. A value of 1
means that the inlet fluid is
superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor void fraction
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal inlet specific enthalpy — Inlet fluid specific enthalpy
400
kJ/kg
(default)  positive scalar
Inlet specific enthalpy for the PB orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific enthalpy
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB nominal inlet specific internal energy — Inlet specific internal energy
400
kJ/kg
(default)  positive scalar
Inlet specific internal energy for the PB orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific internal energy
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB constant orifice nominal mass flow rate — Nominal mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a constant PB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
Note:
This parameter is enabled only when the PB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PB constant orifice nominal pressure drop — Nominal pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a constant PB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
Note:
This parameter is enabled only when the PB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PB constant orifice Cv flow coefficient — Flow coefficient
4
(default)  positive scalar
Value of the constant C_{v} flow coefficient for the PB orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
Note:
This parameter is enabled only when the PB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PB orifice maximum Cv flow coefficient — C_{v} coefficient that corresponds to maximally open component
4
(default)  positive scalar
Value of the C_{v} flow coefficient when the PB orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB orifice Cv flow coefficient vector — C_{v} coefficients for values in member position vector
[1e06, .8, 1.6, 2.4, 3.2, 4]
(default)  1byn vector
Vector of C_{v} flow coefficients. Each coefficient corresponds to a value in the PB orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the PB orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB constant orifice Kv flow coefficient — Flow coefficient
3.6
(default)  positive scalar
Value of the constant K_{v} flow coefficient for the PB orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
Note:
This parameter is enabled only when the PB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PB orifice maximum Kv flow coefficient — K_{v} coefficient that corresponds to maximally open component
3.6
(default)  positive scalar
Value of the K_{v} flow coefficient when the PB orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB orifice Kv flow coefficient vector — K_{v} coefficients for values in member position vector
[1e06, .72, 1.44, 2.16, 2.88, 3.6]
(default)  1byn vector
Vector of K_{v} flow coefficients. Each coefficient corresponds to a value in the PB orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the PB orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB orifice spool travel vector — Vector of spool opening distances relative to fully closed position
[0, .00125, .0025, .00375, .005]
m
(default)  1byn vector
Vector of spool travel distances for the tabular parameterization of the valve area. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
PB maximum orifice area — Maximum orifice opening area
1e4 m^2
(default)  positive scalar
Largest open area of the PB orifice during the operation of the valve.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toLinear
.
PB orifice area vector — Vector of valve opening areas
[1e10, 1e05, 4e05, 6e05, .0001]
m^2
(default)  1byn vector
Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond onetoone with the elements in the PB orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toTabulated
.
PB constant orifice area — Crosssectional area for constant orifice
1e4 m^2
(default)  positive scalar
Orifice area when the positive and negative spool positions include the same orifice.
Dependencies
To enable this parameter, set one of the following settings in each parameter:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
orLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
Note:
This parameter is enabled only when the PB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
PB orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
0.7
(default)  positive scalar
Ratio between the inlet pressure, p_{in}, and the outlet pressure, p_{out}, defined as $$({p}_{in}{p}_{out})/{p}_{in}$$ where choking first occurs for the PB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
orCv flow coefficient
At least one of the following parameters:
Positive spool position open connections to:
PB, AT
PA, PB
PB
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to:
PA, PB, AT, BT
PB, AT
PB, BT
PA, PB
PB
PA, PB, AB
AB Orifice
Spool position at maximum AB orifice area — Spool offset for fully open AB orifice
5e3 m
(default)  positive scalar
Spool offset from the neutral position for a fully open AB orifice.
Dependencies
To enable this parameter, set one of these parameters.
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
Note:
This parameter is enabled only when the AB orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AB spool travel between closed and open orifice — Maximum spool stroke
0.005 m
(default)  positive scalar
Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toLinear  Area vs. spool travel
orLinear  Nominal mass flow rate vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toLinear
.
AB nominal mass flow rate at maximum orifice opening — Rated mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a maximally open AB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal pressure drop at maximum orifice opening — Rated pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a maximally open AB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal inlet condition specification — Method of determining inlet fluid state
Temperature
(default)  Vapor quality
 Vapor void fraction
 Specific enthalpy
 Specific internal energy
Method of determining the inlet fluid state for AB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal inlet pressure — Inlet fluid pressure
0.101325
MPa
(default)  positive scalar
Inlet pressure for the AB orifice at nominal conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal inlet temperature — Fluid temperature
293.15
K
(default)  positive scalar
Inlet fluid temperature for the AB orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Temperature
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal inlet vapor quality — Inlet vapor quality mass fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor quality by mass fraction for the AB orifice in nominal operating
conditions. A value of 0
means that the inlet fluid
is subcooled liquid. A value of 1
means that the
inlet fluid is superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor quality
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal inlet vapor void fraction — Inlet vapor void fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor void fraction for the AB orifice in nominal operating conditions. A
value of 0
means that the inlet fluid is subcooled
liquid. A value of 1
means that the inlet fluid is
superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor void fraction
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal inlet specific enthalpy — Inlet fluid specific enthalpy
400
kJ/kg
(default)  positive scalar
Inlet specific enthalpy for the AB orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific enthalpy
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB nominal inlet specific internal energy — Inlet specific internal energy
400
kJ/kg
(default)  positive scalar
Inlet specific internal energy for the AB orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific internal energy
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB constant orifice nominal mass flow rate — Nominal mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a constant AB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
Note:
This parameter is enabled only when the AB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AB constant orifice nominal pressure drop — Nominal pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a constant AB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
Note:
This parameter is enabled only when the AB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AB constant orifice Cv flow coefficient — Flow coefficient
4
(default)  positive scalar
Value of the constant C_{v} flow coefficient for the AB orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
Note:
This parameter is enabled only when the AB orifice settings appear all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AB orifice maximum Cv flow coefficient — C_{v} coefficient that corresponds to maximally open component
4
(default)  positive scalar
Value of the C_{v} flow coefficient when the AB orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB orifice Cv flow coefficient vector — C_{v} coefficients for values in member position vector
[1e06, .8, 1.6, 2.4, 3.2, 4]
(default)  1byn vector
Vector of C_{v} flow coefficients. Each coefficient corresponds to a value in the AB orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the AB orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB constant orifice Kv flow coefficient — Flow coefficient
3.6
(default)  positive scalar
Value of the constant K_{v} flow coefficient for the AB orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
Note:
This parameter is enabled only when the AB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AB orifice maximum Kv flow coefficient — K_{v} coefficient that corresponds to maximally open component
3.6
(default)  positive scalar
Value of the K_{v} flow coefficient when the AB orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB orifice Kv flow coefficient vector — K_{v} coefficients for values in member position vector
[1e06, .72, 1.44, 2.16, 2.88, 3.6]
(default)  1byn vector
Vector of K_{v} flow coefficients. Each coefficient corresponds to a value in the AB orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the AB orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AB orifice spool travel vector — Vector of spool opening distances relative to fully closed position
[0, .00125, .0025, .00375, .005]
m
(default)  1byn vector
Vector of spool travel distances for the tabular parameterization of the valve area. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
AB maximum orifice area — Maximum orifice opening area
1e4 m^2
(default)  positive scalar
Largest open area of the AB orifice during the operation of the valve.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toLinear
.
AB orifice area vector — Vector of valve opening areas
[1e10, 1e05, 4e05, 6e05, .0001]
m^2
(default)  1byn vector
Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond onetoone with the elements in the AB orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toTabulated
.
AB constant orifice area — Crosssectional area for constant orifice
1e4 m^2
(default)  positive scalar
Orifice area when the positive and negative spool positions include the same orifice.
Dependencies
To enable this parameter, set one of the following settings in each parameter:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
orLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
Note:
This parameter is enabled only when the AB orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AB orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
0.7
(default)  positive scalar
Ratio between the inlet pressure, p_{in}, and the outlet pressure, p_{out}, defined as $$({p}_{in}{p}_{out})/{p}_{in}$$ where choking first occurs for the AB orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
orCv flow coefficient
At least one of the following parameters:
Positive spool position open connections to:
PA, PB, AB
Neutral spool position open connections to:
PA, PB, AB
Negative spool position open connections to:
PA, PB, AB
AT Orifice
Spool position at maximum AT orifice area — Spool offset for fully open AT orifice
5e3 m
(default)  positive scalar
Spool offset from the neutral position for a fully open AT orifice.
Dependencies
To enable this parameter, set one of these parameters.
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
Note:
This parameter is enabled only when the AT orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AT spool travel between closed and open orifice — Maximum spool stroke
0.005 m
(default)  positive scalar
Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toLinear  Area vs. spool travel
orLinear  Nominal mass flow rate vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toLinear
.
AT nominal mass flow rate at maximum orifice opening — Rated mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a maximally open AT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal pressure drop at maximum orifice opening — Rated pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a maximally open AT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal inlet condition specification — Method of determining inlet fluid state
Temperature
(default)  Vapor quality
 Vapor void fraction
 Specific enthalpy
 Specific internal energy
Method of determining the inlet fluid state for AT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal inlet pressure — Inlet fluid pressure
0.101325
MPa
(default)  positive scalar
Inlet pressure for the AT orifice at nominal conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal inlet temperature — Fluid temperature
293.15
K
(default)  positive scalar
Inlet fluid temperature for the AT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Temperature
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal inlet vapor quality — Inlet vapor quality mass fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor quality by mass fraction for the AT orifice in nominal operating
conditions. A value of 0
means that the inlet fluid
is subcooled liquid. A value of 1
means that the
inlet fluid is superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor quality
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal inlet vapor void fraction — Inlet vapor void fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor void fraction for the AT orifice in nominal operating conditions. A
value of 0
means that the inlet fluid is subcooled
liquid. A value of 1
means that the inlet fluid is
superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor void fraction
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal inlet specific enthalpy — Inlet fluid specific enthalpy
400
kJ/kg
(default)  positive scalar
Inlet specific enthalpy for the AT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific enthalpy
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT nominal inlet specific internal energy — Inlet specific internal energy
400
kJ/kg
(default)  positive scalar
Inlet specific internal energy for the AT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific internal energy
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT constant orifice nominal mass flow rate — Nominal mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a constant AT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
Note:
This parameter is enabled only when the AT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AT constant orifice nominal pressure drop — Nominal pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a constant AT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
Note:
This parameter is enabled only when the AT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AT constant orifice Cv flow coefficient — Flow coefficient
4
(default)  positive scalar
Value of the constant C_{v} flow coefficient for the AT orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
Note:
This parameter is enabled only when the AT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AT orifice maximum Cv flow coefficient — C_{v} coefficient that corresponds to maximally open component
4
(default)  positive scalar
Value of the C_{v} flow coefficient when the AT orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT orifice Cv flow coefficient vector — C_{v} coefficients for values in member position vector
[1e06, .8, 1.6, 2.4, 3.2, 4]
(default)  1byn vector
Vector of C_{v} flow coefficients. Each coefficient corresponds to a value in the AT orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the AT orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT constant orifice Kv flow coefficient — Flow coefficient
3.6
(default)  positive scalar
Value of the constant K_{v} flow coefficient for the AT orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
Note:
This parameter is enabled only when the AT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AT orifice maximum Kv flow coefficient — K_{v} coefficient that corresponds to maximally open component
3.6
(default)  positive scalar
Value of the K_{v} flow coefficient when the AT orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT orifice Kv flow coefficient vector — K_{v} coefficients for values in member position vector
[1e06, .72, 1.44, 2.16, 2.88, 3.6]
(default)  1byn vector
Vector of K_{v} flow coefficients. Each coefficient corresponds to a value in the AT orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the AT orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
AT orifice spool travel vector — Vector of spool opening distances relative to fully closed position
[0, .00125, .0025, .00375, .005]
m
(default)  1byn vector
Vector of spool travel distances for the tabular parameterization of the valve area. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
AT maximum orifice area — Maximum orifice opening area
1e4 m^2
(default)  positive scalar
Largest open area of the AT orifice during the operation of the valve.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toLinear
.
AT orifice area vector — Vector of valve opening areas
[1e10, 1e05, 4e05, 6e05, .0001]
m^2
(default)  1byn vector
Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond onetoone with the elements in the AT orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toTabulated
.
AT constant orifice area — Crosssectional area for constant orifice
1e4 m^2
(default)  positive scalar
Orifice area when the positive and negative spool positions include the same orifice.
Dependencies
To enable this parameter, set one of the following settings in each parameter:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
orLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
Note:
This parameter is enabled only when the AT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
AT orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
0.7
(default)  positive scalar
Ratio between the inlet pressure, p_{in}, and the outlet pressure, p_{out}, defined as $$({p}_{in}{p}_{out})/{p}_{in}$$ where choking first occurs for the AT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
orCv flow coefficient
At least one of the following parameters:
Positive spool position open connections to
PB, AT
.Neutral spool position open connections to:
PA, PB, AT, BT
PB, AT
AT, BT
PA, AT
AT
PA, AT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PB, AT
.
BT Orifice
Spool position at maximum BT orifice area — Spool offset for fully open BT orifice
5e3 m
(default)  positive scalar
Spool offset from the neutral position for a fully open BT orifice.
Dependencies
To enable this parameter, set one of these parameters.
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
Note:
This parameter is enabled only when the BT orifice settings do not appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
BT spool travel between closed and open orifice — Maximum spool stroke
0.005 m
(default)  positive scalar
Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toLinear  Area vs. spool travel
orLinear  Nominal mass flow rate vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toLinear
.
BT nominal mass flow rate at maximum orifice opening — Rated mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a maximally open BT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal pressure drop at maximum orifice opening — Rated pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a maximally open BT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal inlet condition specification — Method of determining inlet fluid state
Temperature
(default)  Vapor quality
 Vapor void fraction
 Specific enthalpy
 Specific internal energy
Method of determining the inlet fluid state for BT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal inlet pressure — Inlet fluid pressure
0.101325
MPa
(default)  positive scalar
Inlet pressure for the BT orifice at nominal conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal inlet temperature — Fluid temperature
293.15
K
(default)  positive scalar
Inlet fluid temperature for the BT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Temperature
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal inlet vapor quality — Inlet vapor quality mass fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor quality by mass fraction for the BT orifice in nominal operating
conditions. A value of 0
means that the inlet fluid
is subcooled liquid. A value of 1
means that the
inlet fluid is superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor quality
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal inlet vapor void fraction — Inlet vapor void fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor void fraction for the BT orifice in nominal operating conditions. A
value of 0
means that the inlet fluid is subcooled
liquid. A value of 1
means that the inlet fluid is
superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor void fraction
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal inlet specific enthalpy — Inlet fluid specific enthalpy
400
kJ/kg
(default)  positive scalar
Inlet specific enthalpy for the BT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific enthalpy
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT nominal inlet specific internal energy — Inlet specific internal energy
400
kJ/kg
(default)  positive scalar
Inlet specific internal energy for the BT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific internal energy
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT constant orifice nominal mass flow rate — Nominal mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a constant BT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
Note:
This parameter is enabled only when the BT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
BT constant orifice nominal pressure drop — Nominal pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a constant BT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
Note:
This parameter is enabled only when the BT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
BT constant orifice Cv flow coefficient — Flow coefficient
4
(default)  positive scalar
Value of the constant C_{v} flow coefficient for the BT orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
Note:
This parameter is enabled only when the BT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
BT orifice maximum Cv flow coefficient — C_{v} coefficient that corresponds to maximally open component
4
(default)  positive scalar
Value of the C_{v} flow coefficient when the BT orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT orifice Cv flow coefficient vector — C_{v} coefficients for values in member position vector
[1e06, .8, 1.6, 2.4, 3.2, 4]
(default)  1byn vector
Vector of C_{v} flow coefficients. Each coefficient corresponds to a value in the BT orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the BT orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT constant orifice Kv flow coefficient — Flow coefficient
3.6
(default)  positive scalar
Value of the constant K_{v} flow coefficient for the BT orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
Note:
This parameter is enabled only when the BT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
BT orifice maximum Kv flow coefficient — K_{v} coefficient that corresponds to maximally open component
3.6
(default)  positive scalar
Value of the K_{v} flow coefficient when the BT orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Linear
One of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT orifice Kv flow coefficient vector — K_{v} coefficients for values in member position vector
[1e06, .72, 1.44, 2.16, 2.88, 3.6]
(default)  1byn vector
Vector of K_{v} flow coefficients. Each coefficient corresponds to a value in the BT orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the BT orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Tabulated
One of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
BT orifice spool travel vector — Vector of spool opening distances relative to fully closed position
[0, .00125, .0025, .00375, .005]
m
(default)  1byn vector
Vector of spool travel distances for the tabular parameterization of the valve area. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
BT maximum orifice area — Maximum orifice opening area
1e4 m^2
(default)  positive scalar
Largest open area of the BT orifice during the operation of the valve.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toLinear
.
BT orifice area vector — Vector of valve opening areas
[1e10, 1e05, 4e05, 6e05, .0001]
m^2
(default)  1byn vector
Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond onetoone with the elements in the BT orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order.
Dependencies
To enable this parameter, set one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toTabulated
.
BT constant orifice area — Crosssectional area for constant orifice
1e4 m^2
(default)  positive scalar
Orifice area when the positive and negative spool positions include the same orifice.
Dependencies
To enable this parameter, set one of the following settings in each parameter:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
orLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
Note:
This parameter is enabled only when the BT orifice settings appear in all three spool position parameters: Positive spool position open connections, Neutral spool position open connections, and Negative spool position open connections.
BT orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
0.7
(default)  positive scalar
Ratio between the inlet pressure, p_{in}, and the outlet pressure, p_{out}, defined as $$({p}_{in}{p}_{out})/{p}_{in}$$ where choking first occurs for the BT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
orCv flow coefficient
At least one of the following parameters:
Positive spool position open connections to
PA, BT
.Neutral spool position open connections to:
PA, PB, AT, BT
AT, BT
PA, BT
PB, BT
BT
PB, BT, PT
PA, PB, AT, BT, PT
Negative spool position open connections to
PA, BT
.
PT Orifice
Spool position at maximum PT orifice area — Spool offset for fully open PT orifice
5e3 m
(default)  positive scalar
Spool offset from the neutral position for a fully open PT orifice.
Dependencies
To enable this parameter, set Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT spool travel between closed and open orifice — Maximum spool stroke
0.005 m
(default)  positive scalar
Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.
Dependencies
To enable this parameter, set Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toLinear  Area vs. spool travel
orLinear  Nominal mass flow rate vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toLinear
.
PT nominal mass flow rate at maximum orifice opening — Rated mass flow rate
0.1
kg/s
(default)  positive scalar
Typical, rated, or design mass flow rate through a maximally open PT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal pressure drop at maximum orifice opening — Rated pressure drop
0.001
MPa
(default)  positive scalar
Typical, rated, or design pressure drop through a maximally open PT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal inlet condition specification — Method of determining inlet fluid state
Temperature
(default)  Vapor quality
 Vapor void fraction
 Specific enthalpy
 Specific internal energy
Method of determining the inlet fluid state for PT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal inlet pressure — Inlet fluid pressure
0.101325
MPa
(default)  positive scalar
Inlet pressure for the PT orifice at nominal conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal inlet temperature — Fluid temperature
293.15
K
(default)  positive scalar
Inlet fluid temperature for the PT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Temperature
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal inlet vapor quality — Inlet vapor quality mass fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor quality by mass fraction for the PT orifice in nominal operating
conditions. A value of 0
means that the inlet fluid
is subcooled liquid. A value of 1
means that the
inlet fluid is superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor quality
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal inlet vapor void fraction — Inlet vapor void fraction
0
(default)  positive scalar in the range [0,1]
Inlet mixture vapor void fraction for the PT orifice in nominal operating conditions. A
value of 0
means that the inlet fluid is subcooled
liquid. A value of 1
means that the inlet fluid is
superheated vapor.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Vapor void fraction
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal inlet specific enthalpy — Inlet fluid specific enthalpy
400
kJ/kg
(default)  positive scalar
Inlet specific enthalpy for the PT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific enthalpy
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT nominal inlet specific internal energy — Inlet specific internal energy
400
kJ/kg
(default)  positive scalar
Inlet specific internal energy for the PT orifice in nominal operating conditions.
Dependencies
To enable this parameter, set:
Modeling option to
Liquid operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Linear  Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to
Specific internal energy
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT orifice maximum Cv flow coefficient — C_{v} coefficient that corresponds to maximally open component
4
(default)  positive scalar
Value of the C_{v} flow coefficient when the PT orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Linear
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT orifice Cv flow coefficient vector — C_{v} coefficients for values in member position vector
[1e06, .8, 1.6, 2.4, 3.2, 4]
(default)  1byn vector
Vector of C_{v} flow coefficients. Each coefficient corresponds to a value in the PT orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the PT orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Cv flow coefficient
Opening characteristic to
Tabulated
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT orifice maximum Kv flow coefficient — K_{v} coefficient that corresponds to maximally open component
3.6
(default)  positive scalar
Value of the K_{v} flow coefficient when the PT orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Linear
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT orifice Kv flow coefficient vector — K_{v} coefficients for values in member position vector
[1e06, .72, 1.44, 2.16, 2.88, 3.6]
(default)  1byn vector
Vector of K_{v} flow coefficients. Each coefficient corresponds to a value in the PT orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the PT orifice spool travel vector parameter.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
Opening characteristic to
Tabulated
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
PT orifice spool travel vector — Vector of spool opening distances relative to fully closed position
[0, .00125, .0025, .00375, .005]
m
(default)  1byn vector
Vector of spool travel distances for the tabular parameterization of the valve area. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.
Dependencies
To enable this parameter, set Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
And either:
Modeling option to
Liquid operating condition
, Area characteristics toDifferent for each flow path
, and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Area characteristics toDifferent for each flow path
, and Opening characteristic toTabulated
.
PT maximum orifice area — Maximum orifice opening area
1e4 m^2
(default)  positive scalar
Largest open area of the PT orifice during the operation of the valve.
Dependencies
To enable this parameter, set Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toLinear  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toLinear
.
PT orifice area vector — Vector of valve opening areas
[1e10, 1e05, 4e05, 6e05, .0001]
m^2
(default)  1byn vector
Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond onetoone with the elements in the PT orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order.
Dependencies
To enable this parameter, set Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
Also set Area characteristics to
Different for each flow path
and
either:
Modeling option to
Liquid operating condition
and Orifice parameterization toTabulated data  Area vs. spool travel
.Modeling option to
Vapor operating condition
, Orifice parameterization toOrifice area
, and Opening characteristic toTabulated
.
PT orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
0.7
(default)  positive scalar
Ratio between the inlet pressure, p_{in}, and the outlet pressure, p_{out}, defined as $$({p}_{in}{p}_{out})/{p}_{in}$$ where choking first occurs for the PT orifice.
Dependencies
To enable this parameter, set:
Modeling option to
Vapor operating condition
Area characteristics to
Different for each flow path
Orifice parameterization to
Kv flow coefficient
orCv flow coefficient
Neutral spool position open connections to:
PT
PA, AT, PT
PB, BT, PT
PA, PB, AT, BT, PT
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Version History
Introduced in R2024b
MATLAB Command
You clicked a link that corresponds to this MATLAB command:
Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
How to Get Best Site Performance
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Americas
 América Latina (Español)
 Canada (English)
 United States (English)
Europe
 Belgium (English)
 Denmark (English)
 Deutschland (Deutsch)
 España (Español)
 Finland (English)
 France (Français)
 Ireland (English)
 Italia (Italiano)
 Luxembourg (English)
 Netherlands (English)
 Norway (English)
 Österreich (Deutsch)
 Portugal (English)
 Sweden (English)
 Switzerland
 United Kingdom (English)