# Controlled Volumetric Flow Rate Source (TL)

Generate time-varying volumetric flow rate

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

## Description

The Controlled Volumetric Flow Rate Source (TL) block represents an ideal mechanical energy source in a thermal liquid network. The volumetric flow rate is controlled by the input physical signal at port V. The source can maintain the specified 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

### Input

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Input physical signal that specifies the volumetric flow rate through the source.

### Conserving

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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

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

## Version History

Introduced in R2016a