Hot combustion gases enter the nozzle of a turbojet engine at 260 kPa, 747°C, and 80 m/s, and they exit at a pressure of 85 kPa. Assuming an isentropic efficiency of 92 percent and treating the combustion gases as air, determine the exit temperature.

An adiabatic steam turbine is operating with inlet conditions of 12.5 MPa and 600°C and an exit pressure of 10 kPa. It has an isentropic efficiency of 85%. Determine the steam flow required if it is to produce 250 MW. Determine the exit temperature, the outlet quality (if the outlet conditions are a saturated mixture), and the change in entropy. Also show the process on a T-s diagram with respects to the saturation lines

3. Helium enters an adiabatic 100-mm-diameter pipe steadily, with a velocity of 75 m/s. At the pipe entrance, the gas is at 200 kPa and 20°C; and at the exit, it is at 180 kPa and 18°C. Calculate the rate at which entropy is generated in the pipe, in W/K. (Assume ideal gas behavior and cold-air-standard)

Air is to be compressed steadily and isentropically from 1 atm to 16 atm by a two-stage compressor. To minimize the total compression work, the intermediate pressure between the two stages must be (a) 3 atm (b) 4 atm (c) 8.5 atm (d) 9 atm (e) 12 atm