|Posted: 08 November 2005 at 11:34pm | IP Logged
I am have trouble solving three homework questions and would appreciate some help. The questions are some what involved, but would appreciate any help.
Question 1: Refrigerant-134a enters an adiabatic compressor as sarturated vapor at 160 kPa at a rate of 2m^3/min and is compressed to a pressure of 900 kPa. Find the minimum power that must be supplied to the compressor.
Question 2: A 1.2 ft^3 well-insulated rigid can intitially contains refrigerant-134a at 140 psia and 70 F. Now a crack develops in the can, and the refrigerant starts to leak out slowly, assuming the refigerant remaining in the can has undergone a reversible, adiabatic process. Find the final mass in the can when the pressure drops to 20 psia.
Question 3:Helium gas is compressed from 90kPa and 30C to 450kPa in a reversible, adibatic process. Find the final tempature and the work done, assuming the process takes place (a) in a piston-cylinder
(b) in a steady-flow compressor