Apipe of outside diameter 200mm is lagged with an insulating material of thermal conductivity 0.06 w m-1k-1 and thicknes 75mm. the pipe carries a process fluid at a temperature of 300oc and above the average temperature of the outer surface of the lagging is 45c. (a) estimate the rate of heat loss per meter length of pipe. (b) explain why the thermal resistance of the pipe wall can be ignored.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2