Steady state model equation- pressure and area relationship

[ivoryhorseman]

can sombody help me in deriving the formula( see attched) or suggest books where I could find the same.

 

[georgeverghese]

This is simply not correct - flow into the chamber may be subsonic, while flow out of the chamber may be sonic. Some other combinations of sonic and subsonic flow at the 2 nozzles may also invalidate this formula.

Pls read any flow dynamics text that discusses these 2 flow cases across nozzles or orifices.

 

[gruntguru]

Even if you assume subsonic, incompressible flow, area is inversely proprtional to the square root of pressure so you are missing some exponents at the very least. (Flow is proportional to A x sqrt(delta P))

A quick calc (could be wrong) gives Pc = (A₁²xP₁ + A₂²xP₂)/(A₁² + A₂²)

je suis charlie

 

[ivoryhorseman]

thank you george verghese and gruntguru