Heat is generated in a cylindrical fuel rod in a nuclear reactor according to the relationship ˙ q = ˙ q max [ 1 − ( r r o ) 2 ] q˙=q˙max[1−(rro)2] where ˙ q q˙ is the volumetric heat generation rate, kW/m3, and ro is the outside cylinder radius. Develop the equation that expresses the temperature difference between the rod center line and its surface.

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]