# Isothermal Liquid Predefined Properties (IL)

**Libraries:**

Simscape /
Fluids /
Isothermal Liquid /
Utilities

## Description

The Isothermal Liquid Predefined Properties (IL) block sets the working fluid liquid properties of your isothermal liquid network to the properties of a predefined fluid.

You can also model dissolved air in the system as a function of pressure. To specify your own working fluid properties, use the Foundation Library Isothermal Liquid Properties (IL) block. If you do not specify a fluid, the system defaults apply. See Specify Fluid Properties for more details.

### Fluid Properties Range

You can set the block to model the properties of several predefined different
liquids by using the **Isothermal liquid** parameter.

**Water**

The block provides the water properties between the triple point, when the fluid
temperature and pressure reach `273.160 K`

and ```
611.657
Pa
```

, and the critical point, when the fluid temperature reaches
`647.096 K`

. *P _{min}*
is set by the triple point or the saturation pressure, whichever is
greater.

**Ethylene-, Propylene-, and Glycerol-Water Mixtures**

The block provides the properties for ethylene-glycol, propylene-glycol, and glycerol are provided for temperatures above the solution freezing point. When you visualize properties, the displayed minimum temperature may be lower than the fluid freezing point. The block does not display updated temperatures for different mixture concentrations.

When you specify the mixture, you can define the concentration of ethylene glycol,
propylene glycol, or glycerol to water by mass fraction or volume fraction by
using the **Concentration type** parameter.

The block provides the properties for:

Concentration by mass between 0 and 0.6 and by volume between 0 and 1 for ethylene glycol.

Concentration by mass between 0 and 0.6 and by volume between 0.1 and 0.6 for propylene glycol.

Concentration by mass between 0 and 0.6 for glycerol. You cannot model glycerol concentration by volume.

The block stores the properties as a function of temperature and concentration. The block
maintains all properties, except for density and the thermal expansion
coefficient *α*, as constants for a range of pressures.

**Seawater**

The block provides seawater properties for temperatures between ```
273.15
K
```

and `393.15 K`

and for pressures above the
system saturation pressure. The salinity concentration can range from
`0`

to `0.12`

by mass.

The block stores the properties as tabulated data with respect to pressure and temperature. The block derives the data from the Thermophysical properties of seawater software on the MIT website.

**Aviation Fuel Jet-A**

The block provides properties for a general, representative fuel mixture based on
Jet-A-4658 and Jet-A-3638 surrogates at temperatures between ```
222.22
K
```

and `645.61 K`

and pressures above the
saturation point.

The block stores the properties as tabulated data with respect to pressure and temperature.

**Diesel Fuel**

The block provides diesel properties for temperatures between `238.20 K`

and `690.97 K`

and for pressures above the saturation
point.

**SAE 5W-30**

The block provides SAE 5W-30 properties for temperatures between ```
235.15
K
```

and `473.15 K`

and for pressures above
`0.01 MPa`

. The block bases the properties at the system
temperature and atmospheric pressure measurements for temperatures between
`29.85 °C`

and `74.85 °C`

(```
303
K
```

to ` 348 K`

) and pressures between ```
7
MPa
```

and `87 MPa`

. The block uses curve fits to
define properties in extrapolated regions.

**Lubricating Oils and Hydraulic Fluids**

The block uses numerical approximations to calculate fluid properties for these liquids:

`SAE 30 Oil`

`SAE 50 Oil`

`10W Oil`

`30W Oil`

`50W Oil`

`Skydrol LD-4`

`Skydrol 500B-4`

`Skydrol 5`

`HyJet-IVA`

`Fluid MIL-F-83282`

`Fluid MIL-F-5606`

`Fluid MIL-F-87257`

`ATF (Dexron III)`

`ISO VG 22 (ESSO UNIVIS N 22)`

`ISO VG 32 (ESSO UNIVIS N 32)`

`ISO VG 46 (ESSO UNIVIS N 46)`

`ISO VG 68`

`Brake fluid DOT 3`

`Brake fluid DOT 4`

`Brake fluid DOT 5`

The block uses the Walther equation to approximate changes in velocity,
*v*, with respect to temperature, *T*

$${\mathrm{log}}_{10}\left({\mathrm{log}}_{10}\left(v+a\right)\right)=b-d{\mathrm{log}}_{10}\left(T\right),$$

where *a*, *b*, and
*d* are constants that are specific to each fluid.

The block assumes that the density, *ρ*, changes linearly
with respect to temperature,

$$\rho ={\rho}_{ref}+\alpha \left({T}_{ref}-T\right),$$

where:

*α*are constants that are specific to each fluid.*ρ*is the fluid density at the reference temperature,_{ref}*T*._{ref}

The bulk modulus, *β*, is

$$\beta =\rho {c}^{2},$$

where *c* is the speed of sound. The block
uses *c*
`= 1460 m/s`

as the speed of sound in hydraulic oils.

**Gasoline**

The block uses the same approximations as the lubricating oils and hydraulic fluids to
calculate the gasoline density and bulk modulus. In gasoline, the speed of sound
is `1250 m/s`

.

The Vogel-Fulcher-Tammann equation calculates the fluid viscosity for gasoline,

$${\text{v=v}}_{0}{e}^{\frac{B}{T-{T}_{0}}},$$

where *v _{0}*,

*B*, and

*T*are constants.

_{0}### Dissolved Air

You can optionally model air dissolved into the liquid system. If you select
**Model air dissolution**, the block models dissolution between
the values of the **Atmospheric pressure** parameter and the
**Pressure at which all entrained air is dissolved** parameter
by using Henry's law. For more information, see Fluid Models with Entrained Air.

### Visualizing Fluid Properties

To visualize the fluid density and bulk modulus in your network, right-click the Isothermal
Liquid Predefined Properties (IL) block and select **Fluids** > **Plot Fluid Properties**.

Use the **Reload Data** button to regenerate the plot when the fluid
selection or fluid parameters change.

## Examples

## Ports

### Conserving

## Parameters

## References

[1] Massachusetts Institute of
Technology (MIT). *Thermophysical properties of seawater database*.
http://web.mit.edu/seawater.

[2] K.G. Nayar, M.H. Sharqawy,
L.D. Banchik, J.H. Lienhard V. "Thermophysical properties of seawater: A review and new
correlations that include pressure dependence." *Desalination* 390
(July 2016): 1-24.

[3] M.H. Sharqawy, J.H. Lienhard
V, S.M. Zubair. "Thermophysical properties of seawater: A review of existing
correlations and data." *Desalination and Water Treatment* 16, no.
1-3 (april 2010): 354-380.

[4] I.H. Bell, J. Wronski, S.
Quoilin, V. Lemort. "Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and
the Open-Source Thermophysical Property Library CoolProp." *Industrial &
Engineering Chemistry Research* 53, no. 6 (February 12, 2014):
2498–2508.

## Extended Capabilities

## Version History

**Introduced in R2020a**