Experimental investigation of local heat transfer distribution on smooth and roughened surfaces under an array of angled impinging jets

Measurements of the local heat transfer distribution on smooth and roughened surfaces under an array of angled impinging jets are presented. The test rig is designed to simulate impingement with crossflow in one direction. Jet angle is varied between 30, 60, and 90 deg as measured from the target surface, which is either smooth or randomly roughened. Liquid crystal video thermography is used to capture surface temperature data at,five different jet Reynolds numbers ranging between 15,000 and 35,000. The effect of jet angle, Reynolds number gap, and surface roughness on heat transfer and pressure loss is determined along with the various interactions among these parameters.