Compressible Flow Equation

[1969grad]

Anyone know the derivation of Equation 1-11 in Crane's Tech Paper 410?

To use this formula you have to calculate Y per page A-2.

 

[patrickraj]

I BELIEVE IT HAS BEEN EXPLAINED WELL. Specify your problem I give YOU THE solution.

 

[hacksaw]

the theoretical basis involves integrating bernoulli's equation, under the condition isentropic expansion / compression. It can also be extended to irreversible expansions, under isentahalpic conditions, and to simple friction loss in the present of heat gain (as i recall). this is all text book stuff...

 

[1969grad]

I cannot seem to correlate the Crane 410 equation with my compressible flow textbook. So if anyone can direct me to the dirivation then I would appreciate if you would drop me a note at Lannie_McNeill@willbros.com.

Thanks.

 

[saxon]

1969grad, "Y" in the listed formula is the net expansion factor for compressible flow (gases) through orifices, nozzles or pipe. This is a correction factor needed to compensate for the changes in fluid properties due to expansion of the fluid. This equation was developed by a Frenchman by the name of Darcy and is based on extensive empirical data. I believe it was developed sometime in the latter half of the 19th century.

As for comparison with your text book, the text may be using a different equation, but it should have the fluid expansion taken into account somehow (that is, if it is for compressible fluids). It may have a different nomenclature for it.

Hope this helps.
saxon