Chapter 7, Problem 7.40P

One kg of an ideal gas (gas constant R = 287 J/kg.K) undergoes an irreversible process from state-1 (1 bar, 300 K) to state -2 (2 bar, 300 K). The change in specific entropy (52 - s1) of the gas (in J/kg. K) in the process is

Refrigerant 134a at p₁ = 30 lb/in², T₁ = 40°F enters a compressor operating at steady state with a mass flow rate of 150 lb/h and exits as saturated vapor at p2 = 160 lb/in². Heat transfer occurs from the compressor to its surroundings, which are at To = 40°F. Changes in kinetic and potential energy can be ignored. The power input to the compressor is 1.5 hp. Determine the heat transfer rate for the compressor, in Btu/hr, and the entropy production rate for the compressor, in Btu/hr.°R.

Argon gas flows through a well-insulated nozzle at steady state. The temperature and velocity at the inlet are 550°R and 150 ft/s, respectively. At the exit, the temperature is 480°R and the pressure is 40 lb/in?. The area of the exit is 0.0085 ft². Use the ideal gas model with k-1.67, and neglect potential energy effects. Determine the velocity at the exit, in ft/s, and the mass flow rate, in lb/s. Step 1 Your answer is correct Determine the velocity at the exit, in ft/s. V₂- 677.088 Hint Step 2 ft/s Determine the mass flow rate, in lb/s, through the nozzle. m = i lb/s Attempts: 2 of 4 used