To augment heat transfer between two flowing fluids it is proposed to insert a 100-mm-long, 5-mm-diameter 2024 aluminum pin fin through the wall separating the two fluid.

The pin is inserted to a depth of d into fluid 1. Fluid 1 is air with a mean temperature of 10°C and nearly uniform velocity of 10 m/s. Fluid 2 is air with a mean temperature of 40°C and mean velocity of 3 m/s.

(a) Determine the rate of heat transfer from the warm air to the cool air through the pin fin for d = 50 mm.

(b) Plot the variation of the heat transfer rate with the insertion distance, d. Does an optimal insertion distance exist?

T= 10C, V= 10 m/s Air D= 5 mm L= 100 mm Air T.= 40C, V = 3 m/s