Numerical study on flow and heat transfer in a multi-jet microchannel heat sink

A multi-jet microchannel (MJMC) heat sink with coolant flowing through alternative inlet and outlet jets in the direction normal to the heated surface is studied. Three dimensional flow and heat transfer processes in the MJMC are numerically simulated using the SIMPLE-type finite volume method (FVM). Compared with traditional microchannels, the MJMC combines the advantages of impinging jet flow and entrance effects of microchannels, and thus its cooling performance overwhelms showing less pumping power, lower thermal resistance and improved uniformity of temperature at the bottom surface. Effects of various geometrical parameters including jet numbers, channel aspect ratio, the fin width to channel width ratio and the width of the outlet on the performance of the MJMC are analyzed in detail. It is found that the MJMC with more jets, wider outlet and smaller fin width to channel width ratio offers better cooling performance. While the cooling performance exhibits a non-monotonic trend with the channel aspect ratio, the optimum structure is obtained with an aspect ratio around 6. Under the range of parameters studied, the MJMC heat sink with 7 jets, aspect ratio of 6 and fin width to channel width ratio of 0.5 obtains the best cooling performance. (C) 2020 Elsevier Ltd. All rights reserved.