In a steady flow system, the working fluid flows at a rate of 300kg/min. it enters the system with a pressure of 500kn/m2 , a velocity of 200m/s, internal energy of 2.2mj/kg and a specific volume of 0.42m3 /kg. it exits the system with a pressure of 120kn/m2 , a velocity of 140m/s, internal energy of 1.5mj/kg and a specific volume of 1.5m3 /kg. during its passage through the system the fluid losses 40kj/kg to the surroundings. find: i) the necessary diameters of the inlet and outlet pipes. (12 marks) ii) work done on or by the system. iii) the power developed by the system.

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?