Answer Happy

A thin-film electrical heater dissipating 2000 W/m2 is sandwiched between two 25 mm thick plates whose exposed surface experience convection with a fluid for which T. = 20 °C and a = 200 W/m²K. The thermophysical properties of the plates' material are p = 2500 kg/m3, c = 700 J/kg K and 2 = 5 W/mK. - a) On T-x coordinates, sketch the steady-state temperature distribution for - LSXSL. Calculate the temperatures at the surfaces, x = + L and the midpoint, x = 0. Label this distribution as Case 1. [9 marks] b) Consider conditions for which there is a loss of coolant and existence of a nearly adiabatic condition on the x = + L surface. On the T-X coordinates used for part a). sketch the corresponding steady-state temperature distribution and indicate the temperatures at x = 0, + L. Label this distribution as Case 2 [9 marks] c) With the system operating as described in part b), the surface x = - Lexperiences a sudden loss of coolant (nearly adiabatic condition on the x = - L surface). This situation goes undetected for 15 minutes, at which time the power to the heater is deactivated. Assuming no heat losses from the surfaces of the plates, what is the eventual uniform steady-state temperature distribution in the plates? Show this distribution as Case 3 on your sketch. [7 marks]