# Controlled Pressure Source (TL)

Generate time-varying pressure differential

**Library:**Simscape / Foundation Library / Thermal Liquid / Sources

## Description

The Controlled Pressure Source (TL) block represents an
ideal mechanical energy source in a thermal liquid network. The pressure differential is
controlled by the input physical signal at port **P**. The source can
maintain the specified pressure differential across its ports regardless of the mass flow rate
through the source. There is no flow resistance and no heat exchange with the environment. A
positive signal at port **P** causes the pressure at port
**B** to be greater than the pressure at port
**A**.

The energy balance at the source is a function of the energy flow rates through ports
**A** and **B** and the work done on the fluid:

$${\varphi}_{A}+{\varphi}_{B}+{\varphi}_{work}=0,$$

where:

*ϕ*_{A}is the energy flow rate into the source through port**A**.*ϕ*_{B}is the energy flow rate into the source through port**B**.*ϕ*_{work}is the isentropic work done on the fluid.

The isentropic work term is

$${\varphi}_{work}=\frac{\dot{m}\left({p}_{B}-{p}_{A}\right)}{{\rho}_{avg}},$$

where:

*ϕ*_{work}is the isentropic work done on the thermal liquid.*p*_{A}is the pressure at port**A**.*p*_{B}is the pressure at port**B**.*ρ*_{avg}is the average liquid density,$${\rho}_{avg}=\frac{{\rho}_{A}+{\rho}_{B}}{2}\text{.}$$

### Assumptions and Limitations

There are no irreversible losses.

There is no heat exchange with the environment.

## Ports

### Input

### Conserving

## Parameters

## Extended Capabilities

## See Also

Controlled Mass Flow Rate Source (TL) | Controlled Volumetric Flow Rate Source (TL) | Mass Flow Rate Source (TL) | Pressure Source (TL) | Volumetric Flow Rate Source (TL)

**Introduced in R2013b**