One hundred electrical components each dissipating 25 W, are attached to one surface of a square (0.2 m x 0.2 m) copper plate, and all the dissipated energy is transferred to water in parallel flow over the opposite surface. A protuberance at the leading edge of the plate acts to trip the boundary layer, and the plate itself may be assumed to be isothermal. The water velocity and temperature are u8 = 2m/s and T8 = 17°C, and the water's thermo physical properties may be approximated as v = 0.96 X 10-6 m2/s, k = 0.620 W/m · K, and Pr = 5.2.
(a) What is the temperature of the copper plate?
(b) If each component has a plate contact surface area of 1 cm 2 and the corresponding contact resistance is 2 x 10-4 m2 · K/W, what is the component temperature? Neglect the temperature variation across the thickness of the copper plate.