# Pressure Source (TL)

Generate constant or time-varying pressure differential

**Libraries:**

Simscape /
Foundation Library /
Thermal Liquid /
Sources

## Description

The Pressure Source (TL) block represents an ideal mechanical energy source in a thermal liquid network. The source can maintain the specified pressure differential across its ports regardless of the flow rate through the source. There is no flow resistance and no heat exchange with the environment.

Ports **A** and **B** represent the source inlet and
outlet. The input physical signal at port **P** specifies the pressure
differential. Alternatively, you can specify a constant pressure differential as a block
parameter. A positive pressure differential 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

## Version History

**Introduced in R2013b**