Register to reply 
Compressor Equation 
Share this thread: 
#1
Apr707, 02:54 PM

P: 2

Please give me the equation with a link if possible for determining power for a compressor. I know volume x pressure differential / efficiency but I think the gas being compressed also is a factor. Thank you.



#2
Apr707, 03:06 PM

Sci Advisor
P: 5,095

From my old thermo notes, a nonisentropic compressor has a power of:
[tex]\dot{W} = \frac{\dot{m}C_pT_1}{\eta_c} \left[\left(\frac{P_2}{P_1}\right)^{(\frac{\gamma1}{\gamma})}1\right][/tex] You can see the same equation here: http://www.grc.nasa.gov/WWW/K12/airplane/compth.html 


#3
Apr907, 11:07 PM

P: 230

The site seems to be down at the moment but there are online calculators for recips and centrifs at www.processassociates.com
To to process tools section. 


#4
Apr1107, 11:03 PM

P: 2

Compressor Equation
Fred, from your equation a vacuum pump that has a 1bar/.01bar pressure ratio needs more power than a compressor that has a ratio of 10bar/1bar? Is m the molecular weight or the volume?



#5
Apr1207, 06:08 AM

Sci Advisor
P: 5,095

m is mass flow rate.
I'll have to look around a bit, but a vacuum pump most likely will not be applicable here. I'm not sure, I don't deal with them. 


#6
Nov107, 06:44 AM

P: 1

Hello, I'm working on a model of a fan and I have the characteristic curves Flow/impelled power and flow/total pressure.
I also have the relation of adiabatic compression you have written but it concerns the Head (in meters) and not the mass flowrate. Therefore, my question is : how do you get the outlet pressure of a fan knowing the characteristic curves and the formula with the head ? More clearly that possible to convert the Head (m) into a differential pressure (PoutPin) or even the outlet Pressure of the fan (Pout) ? Thank you for any idea. 


#7
Aug1209, 11:30 AM

P: 1

Hi, somebody knows this formula???
HP= Q * 63 * Ln(Pd/Ps) Is a rare formula that are been used in a pipeline gas. Thanks. Felipe PD: Sorry if I make a mistake in the english, I speak spanish. 


#8
Aug1309, 09:15 AM

P: 735

ie. work required also depends upon the inlet density. 


Register to reply 
Related Discussions  
Air compressor  General Physics  2  
Compressor Oil  Mechanical Engineering  4  
Air Compressor Oil  Mechanical Engineering  3  
Air compressor questions...  Mechanical Engineering  1  
Air Compressor  Electrical Engineering  0 