# Volumetric Flow Rate Source (TL)

Generate constant volumetric flow rate

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

• ## Description

The Volumetric Flow Rate Source (TL) block represents an ideal mechanical energy source in a thermal liquid network. The source can maintain a constant volumetric flow rate regardless of the pressure differential. There is no flow resistance and no heat exchange with the environment. A positive volumetric flow rate causes the fluid to flow from port A to port B.

The volumetric flow rate and mass flow rate are related through the expression

where:

• $\stackrel{˙}{m}$ is the mass flow rate from port A to port B.

• ρA and ρB are densities at ports A and B, respectively.

• $\stackrel{˙}{V}$ is the volumetric flow rate.

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:

• ϕA is the energy flow rate into the source through port A.

• ϕB is the energy flow rate into the source through port B.

• ϕwork is the isentropic work done on the fluid.

The isentropic work term is

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

where:

• ϕwork is the isentropic work done on the thermal liquid.

• pA is the pressure at port A.

• pB is the pressure at port B.

• ρavg 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

### Conserving

expand all

Thermal liquid conserving port. A positive flow rate causes the fluid to flow from port A to port B.

Thermal liquid conserving port. A positive flow rate causes the fluid to flow from port A to port B.

## Parameters

expand all

Desired volumetric flow rate of the fluid through the source.

Area normal to the direction of flow at the source inlet and outlet. The two cross-sectional areas are assumed identical.