Section: Thermodynamics | Type: NAT | Marks: 2
Steam enters a steam turbine at 5 MPa and 600 ℃, and exits as saturated vapor at 50 kPa. Under steady state condition, the turbine loses heat to the surroundings at the rate of 50 kJ per kilogram of steam flowing through the turbine. The ambient temperature is 300 K, and the heat transfer to the surroundings takes place at the outer surface of the turbine at a temperature of 450 K. The irreversibility per unit mass of steam flowing through the turbine is _______ kJ/kg (round off to 2 decimal places). Neglect the change in kinetic and potential energies of the steam, and use the following property values: Superheated steam at 5 MPa, 600 ℃ 3 0.07870 m /kg, 3273.3 kJ/kg, 3666.9 kJ/kg, 7.2605 kJ/(kg K) v u h s = = = = Saturated vapour at 50 kPa 3 3.2403 m /kg, 2483.2 kJ/kg, 2645.2 kJ/kg, 7.5931 kJ/(kg K) g g g g v u h s = = = =
Answer: 132.00 to 134.00