Problem 6.16:
Air is compressed in a steady-state, insulated flow device. The air enters at 1 bar, 25 °C and exits at 5 bar, 200 °C.
a) Determine the amount of work needed for this compression.
b) Calculate the entropy generation.
c) What is the minimum amount of work necessary to compress air from 1 bar, 25 °C to 5 bar?
d) What would be the temperature at the exit of the compressor in part (c)? Assume air to be an ideal gas with Cp = 30 J/molK.
Problem 6.17:
A new compressor has just been delivered to your plant. In order to check its performance you order your staff to make a test run using air. Your staff reports to you the following results: air at a flow rate of 50 mol/min was compressed from 1 bar and 25 °C to 10 bar. The temperature at the exit of the compressor was measured and found to be 450 °C.
a) What is the power (in kW) consumed by the compressor?
b) What is the efficiency of the compressor? Assume air to be an ideal gas with CP = 3.5R.