Forced Convection Teat Transfer from a Cross Circular Yawed Tube.(Dept.M)

Abstract

Complementary heat transfer and flow visualization experiments were performed lo investigate the effect of yaw on tube. Wind tunnel experiments encompassing seven angles of yaw between ᶱ= o( crossflow ) and 28° yielded Nusselt numbers extending over the range of free stream Reynolds numbers from 9000 to 25000. It was found that as the cylinder was yawed with respect to the crossflow orientation, the Nusselt number at first increased, attained a maximum at a yaw angle o 5o and then decreased to a broad minimum which occurred in the range of yaw angles between 20 and 25o and then start to somewhat increase at yaw angle equal 28o. As a further supplement to the heat transfer experiments, the pattern of fluid flow adjacent to the cylinder surface was visualized by means of the oil lampblack technique. The results were compared with the available experimental data. The values of the average Nusselt numbers were fitted in a correlation. This correlation indicates that the Nusselt number is a significant function of Reynolds number and angle of yaw.