A single 'pin fin (Cylindrical)' is to be used in an array of identical pin fins on an electronics heat sink. The fin is made from cast aluminum, k = 180 W/m K, the diameter is 3 mm and the length is 15 mm. There is a heat transfer coefficient of "Y = Last 2 digits of Student ID Number" W/ m² K between the surface of the fin and surrounding air which is at 25°C. (a) Sketch the schematic and Ts-diagrams of the system with complete labeling. (b) Use the expression for a fin with an adiabatic tip to calculate the heat flow through a single pin fin when the base has a temperature of 55°C. (c) Calculate also the efficiency and the effectiveness of this fin design.

3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the atmosphere from outer space. If its original temperature is 38°C, the effective average temperature of the atmosphere is 1093°C, and the effective heat transfer coefficient is , estimate the temperature of the shell after reentry, assuming the time of reentry is 10 min and the interior of the shell is evacuated.

The heat transfer coefficient for a gas flowing over a thin float plate 3-m long and 0.3-m wide varies with distance from the leading edge according to hc(x)=10x1/4Wm2K If the plate temperature is 170C and the gas temperature is 30C, calculate (a) the average heat transfer coefficient, (b) the rate of heat transfer between the plate and the gas, and (c) the local heat flux 2 m from the leading edge. Problem 1.18

A transformer is to be cooled via forced air convection. To increase the effectiveness of thecooling, Alloy 1095 cast aluminum fins are attached to the top of the transformer overwhich air is blown (negligible thermal contact resistance between the transformer and thefins). The fins are 2 cm thick and 7 cm long and span the entire length of the transformer,and the transformer is 7 cm wide and 10 cm long. Air leaves the cooling fan at 25°C .a) Decide how to model the fins before performing any real analysis. Youare willing to accept some error in your analysis and so you will either model thefins as having adiabatic tips or being infinitely long. You expect the average convectioncoefficient over the heat transfer surfaces for this system to be around 50 W m2– K⁄ .Which tip condition should you use for the fins in your analysis? b) Modeling the transformer as being isothermal, determine the average convectioncoefficient over the heat transfer surfaces. Account for heat transfer from the…