1. Calculate the velocity at the exit of a diffuser when air at 100kPa and 20oC enters it with a velocity of 500m/s and exit state is 200kPa and 90oC.
2. R-134a at 800kPa and 100oC enters an adiabatic nozzle steadily with a velocity of 20m/s and leaves as sat-V at 400kPa. Determine 1) temperature at the outlet; 2) the velocity at the outlet; 2) ratio of the inlet to outlet area (A1/A2)
3. A compressor compresses helium from 100kPa and 20oC to 400kPa and 100oC. Helium enters this compressor through a 0.2m2 pipe at a velocity of 15m/s. A heat loss of 200kJ/kg occurs during the compression process. Neglecting the kinetic energy and potential energy, please determine 1) the mass flow rate at the outlet; and 2) the power input to the compressor.
4. Saturated mixture of water at 1500kPa is throttled to 100kPa and 150oC in a steam line. Please calculate the temperature and quality of the water at the inlet.
5. Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. Air enters the heat exchanger at 120kPa and 10oC at a rate of 0.5m3/s. The exhaust gases (cp = 1.2kJ/kg.K) enters at 200oC at a rate of 1.5kg/s and leaves at 80oC. Determine the rate of heat transfer to the air and air temperature at the outlet.