Approximately 106 discrete electrical components can be placed on a single integrated circuit (chip), with electrical heat dissipation as high as 30,000 W/m2. The chip, which is very thin, is exposed to a dielectric liq- uid at its outer surface, with ho = 1000 W/m2 · K and Too,o = 20°C, and is joined to a circuit board at its inner surface. The thermal contact resistance between the chip and the board is 10-4 m2 · K/W, and the board thickness and thermal conductivity are Lb = 5 mm and kb = 1 W/m · K, respectively. The other surface of the board is exposed to ambient air for which hi = 40 and kB = 0.04 W/m · K and thicknesses LA = 10 mm and LB = 20 mm. The contact resistance at the interface between the two materials is known to be 0.30 m2 · K/W. Material A adjoins a fluid at 200°C for which h = 10 W/m2 · K, and material B adjoins a fluid at 40°C for which h = 20 W/m2 · K.
(a) What is the rate of heat transfer through a wall that is 2 m high by 2.5 m wide?
(b) Sketch the temperature distribution.