Compressible Flow Question

[Red_CCF]

Hi

I was wondering, if a flow is compressible, then does that mean that if the inlet and exit of the control volume (same C.S. area) have different densities, would that mean that the temperature and/or pressure of the exit be different than at the inlet (assuming ideal gas)?

If this were the case, then for a vent (and a pump inside of it) that vents from the atmosphere and out to the atmosphere (so P and T conditions are the same at inlet and exit), does this mean that even for very fast flows that the exit air density would be the same as inlet air densities? Would that mean that the compressibility effect will only be detected at very close to the pump and that's where pressure and/or temperature will build up?

Thanks

 

[Navin A S]

for your help.Yes, if a flow is compressible the inlet and exit of the control volume will have different densities if the inlet and exit pressure and temperature are not the same. The compressibility effect will be strongest close to the pump, where the pressure and temperature will be higher than at the inlet and exit. However, depending on the flow rate and size of the vent/pump, the compressibility effect may be negligible.