Steam enters a turbine with a pressure of 30 bar, a temperature of 400 °C, at a velocity of 160 m/s. Steam exits as saturated vapor at 100 °C with a velocity of 100 m/s. At steady state, the turbine develops work at a rate of 540 kJ per kg of steam flowing through the turbine. Heat transfer between the turbine and its surroundings occurs at an average surface temperature of 500 K. Determine the exergy destruction per unit mass of steam flowing through the turbine. Neglect the change in potential energy and let T0 = 25 °C P0 = 1.014 bar.