At steady state, steam with a mass flow rate of 5 kg/s enters a turbine at 400o c and 40 bar and expands to 3 bar. the power developed by the turbine is 2127 kw. the steam then passes through a heat exchanger with a negligible change in pressure, exiting at 400o c. air enters the heat exchanger in a separate stream at 1.4 bar, 820 k and exits at 1.2 bar, 590 k. determine the rate of entropy production for the turbine and heat exchanger. neglect changes in kinetic and potential energy and assume the turbine is adiabatic.

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.