Compressor Efficiency 1

[patibar]

What is the significance of using both adiabatic and polytropic efficiencies for compressors?

Why we calculate both efficiencies?

 

[zdas04]

Because there are different kinds of compressors? Adiabatic exponents work well for positive displacement machines, but not so well for dynamic machines. Polytropic exponents are pretty much meaningless for PD machines.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[patibar]

In Unisim/Hysys it is required to input one of the efficiency. (Adiabatic or Polytropic) Then it calculates the other efficiency irrespective of compressor type (Centrifugal/Reciprocating/Screw).

 

[25362]

See for reference:

http://www.enggcyclopedia.com/2011/11/compressor-power-efficiency-equations/

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