Reconsider Prob. 7-109E. Using EES (or other) software, evaluate and plot the work of compression and entropy change of the helium as functions of the polytropic exponent as it varies from 1 to 1.667. Discuss your results.
Prob. 7-109E
Helium gas is compressed from 16 psia and 85°F to 120 psia at a rate of 10 ft3/s. Determine the power input to the compressor, assuming the compression process to be
(a) Isentropic,
(b) Polytropic with n = 1.2,
(c) Isothermal, and
(d) Ideal two-stage polytropic with n = 1.2.