Question 4. (40 marks] Steam flowing through a pipe that is covered with an insulating material that comprise of two different materials (A and B) as shown in Figure 2. It entire outer surface area is exposed to air for which h= 15 W/m.Kand T = 300 K, Determine: a) Sketch the thermal circuit of the system, b) Total heat loss from the pipe. c) TA d) T (10 marks) (10 marks) (10 marks) (10 marks) (Assume an infinite contact resistance in the interface between A and B, and the pipe wall temperature was uniform and maintained at Tus = 500 K 11 = 50 mm, 12 = 100 mm, k, = 4 W/mK, and ke=0.5 Wim.K). TS Steam TS B Figure 2 steam flowing in a pipe Question 5. [20 marks) Calculate the thermal diffusivity a for the following materials using table 1 a) (10 marks) Pure iron at 300K? (show your steps) b) (10 marks) Pure iron at 500K? (Show your steps) Table A1 Composition T(K) Pikgim) Cp ( JK) K(Wim.K) Pure iron 300 7870 80.2 400 69.5 600 574 54.7 447 490