The effect of drainage configuration on heat transfer under an impinging liquid jet array

The heat transfer characteristics of single and dual-exit drainage configurations for arrays of liquid jets impinging normal to a heated isoflux plate has been studied experimentally. The interaction of drainage channel crossflow from upstream jets and the stagnation jets and its impact on heat transfer was the focus of the investigation. Infrared thermography was used to measure the local temperature distribution on the healed plate, from which local hear transfer coefficients were determined. A single jet diameter was used, and jet arrays with jet-to-jet spacings of 4.8, 6, 8, and 12 jet diameters were studied. Average jet Reynolds numbers in the range 400-5000 were investigated for jet nozzle to-impingement plate spacings of 1, 2, and 4 jet diameters for fully flooded (submerged) drainage flow. A single jet-to-plate spacing large enough to yield free-surface jets was also studied. The data reveal a complex dependence of focal and average Nusselt numbers on the geometric parameters which describe the problem configuration.