Horsepower equation for isentropic positive dispacement gas compressor
Horsepower equation for isentropic positive dispacement gas compressor
(OP)
I have been able to find the equation for an air compressor that takes into account RPM, CID, compression ratio and efficiency and I have seen the non-positive equation that takes into account the input temperature and pressure cp and cv of a gas but I haven't been able to find an equation for a positive dispacement compressor that takes the properties of the gas into account. Thank you to everyone who takes the time to help me.





RE: Horsepower equation for isentropic positive dispacement gas compressor
David
RE: Horsepower equation for isentropic positive dispacement gas compressor
VN = EXP(.344 - .18715 * (SPGR - .05))
CON = (VN - 1!) / VN
CPC = 708.75 - 57.5 * SPGR
CTC = 169.01 + 314.001 * SPGR
Ratio = Press Disch / press Suc
Temp Disch = ((temp suc + 460) * Ratio ^ CON) - 460!
TRG = (temp suc + 460!) / CTC
PRG = Press Suc / CPC
Zfac Suc = 1! + (.0703 * PRG / TRG) * (1! - 6! / TRG ^ 2)
TRG = (temp Disch + 460!) / CTC
PRG = Press Disch / CPC
Zfac disc = 1! + (.0703 * PRG / TRG) * (1! - 6! / TRG ^ 2)
Zavg = (zfac suc + zfac disch)/2
Brake Horsepower per MMSCFDM = (ts + 460) / 520 * (50.8 * (Ratio) ^ CON - 1!) * (Ratio) - .715)) / (CON * (ratio - .793)) * ZAVG
RE: Horsepower equation for isentropic positive dispacement gas compressor
Brake Horsepower per MMSCFDM = (ts + 460) / 520 * (50.8 * (Ratio) ^ CON - 1!) * (Ratio) - .715)) / (CON * (ratio - .793)) * ZAVG
How do I get specific gravity for a gas? Isn't this dependent on pressure? Is there a conversion for perhaps molecular weight? Or should I use the density at the low pressure?
RE: Horsepower equation for isentropic positive dispacement gas compressor
RE: Horsepower equation for isentropic positive dispacement gas compressor
RE: Horsepower equation for isentropic positive dispacement gas compressor
RE: Horsepower equation for isentropic positive dispacement gas compressor
RE: Horsepower equation for isentropic positive dispacement gas compressor
A similar subject was discussed in thread71-109890: Intake temps and IC piping questions.