An electrical power transformer of diameter 250 mm and height 600 mm dissipates 1200 W. It is desired to maintain its surface temperature at 58°C by supplying glycerin at 24°C through thin-walled tubing of 20-mm diameter welded to the lateral surface of the transformer. All the heat dissipated by the transformer is assumed to be transferred to the glycerin.
(a) Assuming the maximum allowable temperature rise of the coolant to be 6°C and fully developed flow throughout the tube, determine the required coolant flow rate, the total length of tubing, and the lateral spacing S between turns of the tubing.