1. Air is expanded from 1.5MPa and 177°C to 90kPa in an adiabatic turbine. Determine the isentropic efficiency of this turbine if the air is exhausted at 0°C
2. Long cylindrical steel rods (?=7833kg/m3 and cp=0.465kJ/kg?°C) of 8?cm diameter are heat treated by drawing them at a velocity of 4m/min through an 8?m?long oven maintained at 900°C.
If the rods enter the oven at 25°C and leave at 750°C, determine (a) the rate of heat transfer to the rods in the oven and (b) the rate of entropy generation associated with this heat transfer process.