Effects of Shallow-Angle Jet Impingement and Free Stream Velocity on Heat Transfer

Experimental studies are carried out to investigate the heat transfer characteristics involving an impinging jet with a shallow-angle in a crossflow. Liquid crystal technique is employed to measure the wall temperature and obtain the heat transfer coefficients. In the study, the Reynolds number for the crossflow is range from 80,000 to 160,000 and the Reynolds number for the jet varies from 20,000 to 40,000. The jet-to-crossflow velocity ratio changes from 2.4 to 4.9. For a constant velocity ratio R = 3.5, it is found that the structure of heat transfer changes in nature as both Reynolds number increases. In addition, it is observed that the heat transfer in the wall jet region is uniquely determined by the jet and is independent of the crossflow. A correlation is constructed to fit data and predict the Nusselt number in this region.