Mass Flow Rate Source (TL)

Generate constant mass flow rate

Libraries:
Simscape / Foundation Library / Thermal Liquid / Sources

Description

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

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

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

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

Parameters

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Select whether the source performs work on the fluid flow:

• `Isentropic power` — The source performs isentropic work on the fluid to maintain the specified mass flow rate. Use this option to represent an idealized pump or compressor and properly account for the energy input and output, especially in closed-loop systems.

• `None` — The source performs no work on the flow, neither adding nor removing power, regardless of the mass flow rate produced by the source. Use this option to set up the desired flow condition upstream of the system, without affecting the temperature of the flow.

Desired mass 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.

Version History

Introduced in R2013b

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