1) Air at the inlet of a nozzle is at 500 kPa, 42.2oC, and a velocity of 87 m/s. The nozzle exit pressure is at 132 kPa. Determine the nozzle exit velocity (m/s) if the adiabatic efficiency is 88.2%. Assume constant specific heats evaluated at 300 K (Cp = 1.005 kJ/kg-K, Cv = 0.718, and k = 1.4).
2) Air at the inlet of an ideal (reversible-adiabatic) compressor enters through a 0.037 m2 pipe at 141 kPa. The compressor exit pressure is at 540 kPa. Calculate the area (cm2) of the exit pipe if the inlet and exit velocities are equal. Assume constant specific heats evaluated at 300 K.
3) An insulated mixing box in an air-conditioning system is used to mix two streams of refrigerant R134a to produce a single stream. The pressure of each stream is 6 bar. Inlet 1 is a saturated vapor with a flow rate of 0.34 kg/s, and inlet 2 is at 40oC with a flow rate of 0.242 kg/s. Determine the rate of entropy production in the mixing box (kW/K). Assume steady state operating conditions.