Combustion gases flow into a boiler (non-mixing, insulated from the surroundings) at 2000k, 1 bar. there is no pressure loss on the gas side and the gases exit at 800k. saturated water enters the boiler at 6 mpa and exits as saturated vapor at 6 mpa. the water flow rate is 10 kg/s. the specific heat at constant pressure is .

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.