One-dimensional plane wall of thickness 2L=80 mm experiences uniform thermal generation of q dot =1000 W/m^3 and is convectively cooled at x=±40m by an ambient fluid characterized by T [infinity] = 30 degrees C. If the steady-state temperature distribution within the wall is T(x) = a(L2-x2)+b where a = 15o C/m^2 and b=40oC, what is the thermal conductivityof the wall? What is the value of the convection heat transfer coefficient?

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]