Slot jet impingement heat transfer from circular cylinders

The heat transfer characteristics of circular cylinders exposed to slot jet impingement of air has been studied experimentally. The study focused on R eynolds numbers (based on nozzle average exit velocity and cylinder diamete r) in the range 600-8000. Both contoured orifice and sharp-edged orifice je t configurations were investigated for cylinder diameter-to-jet width spaci ngs of 0.66, 1.0 and 2.0, and for jet exit-to-nozzle width spacings in the range 1 < z/w < 11. Reference measurements were made with the same cylinder in infinite parallel flow in a wind tunnel. The results reveal that the sl ot jet yields considerably higher average heat transfer from the cylinder w hen compared to the infinite parallel flow case on the basis of identical a verage velocity in the slot jet and infinite flow configurations. As with s lot jet impingement heat transfer from flat surfaces, there appears to be a nozzle-to-cylinder spacing, scaled by nozzle width, which exhibits a maxim um in heat transfer. The average heat transfer characteristics of the cylin der are correlated empirically. (C) 2000 Elsevier Science Ltd. All rights r eserved.