[beyonder1]

Hi all,
I used gas compressor performance macro and i got a lot of variables. These are inbuilt macros. Is there some documentation of these macros where i can learn how these have been obtained? I am unable to figure out the meaning of these terms. Please help me out.

[bparrelli]

Which variables are you having trouble with? I can probably help you define them.

[beyonder1]

These are the expressions : (Mainly efficiency variables)


effPTS = ((gamma-1)/gamma)*log10(pOut/pTotalIn)/log10(tTotalOut/tTotalIn)
effPTT = ((gamma-1)/gamma)*log10(pTotalOut/pTotalIn)/log10(tTotalOut/tTotalIn)
effTS = (1-(pOut/pTotalIn)^((gamma-1)/gamma))/(1-tTotalOut/tTotalIn)
effTT = (1-(pTotalOut/pTotalIn)^((gamma-1)/gamma))/(1-tTotalOut/tTotalIn)


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It would be great if you could point me to some manual where all these are defined. I couldn't find the exact definitions of these.

[turbo]

"P" stands for the polytropic efficiency, while no "P" is the isentropic.
"TT" means the total-to-total.

[bparrelli]

See comments in red:

Originally Posted by shubham2941

These are the expressions : (Mainly efficiency variables)


effPTS = ((gamma-1)/gamma)*log10(pOut/pTotalIn)/log10(tTotalOut/tTotalIn)
total-to-static polytropic efficiency
effPTT = ((gamma-1)/gamma)*log10(pTotalOut/pTotalIn)/log10(tTotalOut/tTotalIn)
total-to-total polytropic efficiency
effTS = (1-(pOut/pTotalIn)^((gamma-1)/gamma))/(1-tTotalOut/tTotalIn)
total-to-static isentropic efficiency
effTT = (1-(pTotalOut/pTotalIn)^((gamma-1)/gamma))/(1-tTotalOut/tTotalIn)
total-to-total isentropic efficiency

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It would be great if you could point me to some manual where all these are defined. I couldn't find the exact definitions of these.

Polytropic or "small-stage" efficiency is what is most common for compressors. Isentropic efficiency is the more well-known definition. Both are defined here in on pp. 52-57 of the PDF link below. The total-to-total means you are using the total pressure at both locations and total-to-static means you are using the static pressure at the exit (usually more common for component efficiencies). On a different note, I would highly recommend downloading and keeping this book below. It's a great turbomachinery reference. Best of luck!

https://www.google.com/url?sa=t&rct=...RmehPC_uKx7TcA