An Experimental Investigation of Liquid Jet Array and Single Phase Spray Impingement Cooling Using Polyalphaolefin

Experiments on triangular and rectangular array jet impingement and single phase spray cooling have been performed to determine the effect of both cooling techniques on heat transfer coefficient and the coolant mass flux required for a given cooling load. Experiments were performed with circular orifices and nozzles for different H/D values from 1.5 to 26 and Reynolds number range of 219 to 837, which is quite lower than the ranges used in widely used correlations. The coolant used was polyalphaolefin. For the custom fabricated orifices, commercial nozzles and conditions used in this study, both cooling techniques showed enhancement of heat transfer coefficient as H/D increases to a certain limit after which it starts to decrease. The heat transfer coefficient always increases with Reynolds number. In keeping with previous studies, single-phase spray cooling technique can provide the same heat transfer coefficient as jets at a slightly lower mass flux, but with a higher pressure head.