How to pass a volumetric flowrate in a gas network on simscape without using volumetric flowrate source ?

Hi everyone,

i'm modeling a gas network which is based on volumetric flowrate passing through components. The purpose is to apply contol and regulations on pressure and volumetric flowrate. But i don't know how to pass te specified volumetric flowrate in the network. When i add a volumetric flowrate source, it may slightly affects the stability of the volumetric flowrate delivered when the parameter "power added" is setted on "none". A gas properties block is attached on the circuit to define the thermodynamics properties of the gas

Also, should i rather connect the volumetric flowrate source before or after the valve ?

Thank you for your help.

[Lina]

Here the model