Monday, May 14, 2007

HW #8, P2 - Isentropic Efficiency of a CO2 Compressor - 4 pts

Carbon dioxide enters an adiabatic compressor at 100 kPa and 300 K at a rate of 2.2 kg/s and exits at 600 kP and 450 K. Neglecting changes in kinetic and potential energies, determine the isentropic efficiency of the compressor.

2 comments:

Anonymous said...

I could use a hint on how to do this. I know how to get the reversible work and I know how to get the entropy generated in the actual process, but because there's no constant temperature reservoir (or constant temperature surroundings), I'm not sure how to translate that into Qact (and thus into Wact).

Dr. B said...

Anon:
You calculate work actual using the 1st Law. The compressor is adiabatic, Qactual = 0. You can lookup H for the inlet and outlet, so it should not be difficult to calculate Wactual. You already did the hard part !