Compressible Gas Pressure Drop Reference 1

[bigpec85]

Hi,

I am looking for a reference for a compressible gas pressure drop method.

The method calculates a critical value based on specific heat ratio and a dimensionless Mach number (using superficial mass flow). This critical value is then compared to an actual value (8f/d).

The relationship between the critical and actual values then determines where a sub, critical or super critical pressure drop equation is performed.

Anyone help?

 

[Latexman]

I believe I've seen such a method in Volume 1 of "The dynamics and thermodynamics of compressible fluid flow" by Ascher H. Shapiro.

Good luck,
Latexman

 

[PaoloPemi]

this seems the usual way to proceed
a) calculate gas speed of sound based on cp/cv
b) calculate actual velocity (based on mass flow and density)
c) compare values and for subcritical flows adopt specific correlations (there are many of these)...
but perhaps I misunderstand the question...

 

[sheiko]

There are two ways in order to calculate the pressure drop of a compressible fluid in a line: isothermal and adiabatic. Both are iterative. However, most calculations are based on the isothermal condition (gas temperature is constant throughout the line). In this case, the specific heat ratio (k) should be omitted from the Mach number and critical pressure calculations. You will find the equations and procedures in any fluid mechanics textbook or on the internet.

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