One hundred electrical components, each dissipating25 W,

Chapter 7, Problem 7.35

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One hundred electrical components, each dissipating25 W, are attached to one surface of a square(0.2 m0.2 m) copper plate, and all the dissipatedenergy is transferred to water in parallel flow over the opposite surface. A protuberance at the leadingedge of the plate acts to tripthe boundary layer, and the plate itself may be assumed to be isothermal. Thewater velocity and temperature are u??2 m/s andT??17?C, and the waters thermophysical propertiesmay be approximated as ??0.9610?6m2/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 areaof 1 cm2and the corresponding contact resistance is210?4m2?K/W, what is the component temper-ature? Neglect the temperature variation across thethickness of the copper plate.