Chapter 6, Problem 6.59P

Refrigerant 134a enters an insulated diffuser as a saturated vapor at 80°F with a velocity of 1400 ft/s. The inlet area is 1.4 in². At the exit, the pressure is 400 lbf/in² and the velocity is negligible. The diffuser operates at steady state and potential energy effects can be neglected. Determine the mass flow rate, in lb/s, and the exit temperature, in °F. Step 1 Determine the mass flow rate, in lb/s. m = i lb/s.

Saturated water vapor at 300°F enters a compressor operating at steady state with a mass flow rate of 5 lb/s and is compressed adiabatically to 600 lbf/in.² If the power input is 2150 hp, determine for the compressor: (a) the percent isentropic compressor efficiency and (b) the rate of entropy production, in hp/°R. Ignore kinetic and potential energy effects.

Consider 5.0 pounds per minute of water vapor at 100 lbf/in², 500°F, and a velocity of 100 ft/s entering a nozzle operating at steady state and expanding adiabatically to the exit, where the pressure is 40 lbf/in2. The isentropic nozzle efficiency is 85.0%. Determine the velocity of the steam at the exit, in ft/s, and the rate of entropy production, in Btu/min.°R.