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GPSA 12TH ED FIG 13-27 ATTACHED

GPSA 12TH ED FIG 13-27 ATTACHED

(OP)
hello i have a question regarding this figure

take fluid with k = 1.30 and a compression ratio of 9 go x direction and meet curve which is about 72% isentropic efficiency following the curved path and 72% polytropic efficiency

if we take the straight vertical lines we would read about 64% isentropic and about 76% polytropic efficiency

but isentropic efficiency is always greater than polytropic efficiency?

Comments>

a request please respond if you have a definite explanation, if it is only a conjecture please ignore

thank you

RE: GPSA 12TH ED FIG 13-27 ATTACHED

The curved lines on the right are lines of constant polytropic efficiency. Lines of constant isentropic efficiency are vertical ie the RH dot on your red line sits at 72% polytropic and 64% isentropic efficiency.

Isentropic efficiency is always less than polytropic for compressors. For expanders its the other way around.

je suis charlie

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