Heat Transfer Characteristics of a Microchannel Heat Sink with Highly-Dense Micro-Jet Arrays

This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks (∼120 jet per cm² with jet width of 0.35 mm). Parametric study is performed to investigate the influence of structure and flow parameters on the convective heat transfer of water jet cooling in confined space. The simulation results show that the optimal jet width, jet spacing and impingement distance are around 0.2 mm, 0.2 mm and 0.3 mm, respectively, which can achieve a low thermal resistance as well as a relatively low pressure drop. The analysis of the heat transfer pathways shows that the micro-fin jet structures can extend the impinging heat transfer area and conduct a considerable proportion of heat, which can reach up to 38.9% with the Reynolds number ranging from 797.1 to 5602.2. The heat transfer characteristics in the heat sink will shift from impingement dominated heat transfer to the channel-convection dominated heat transfer as the jet impingement distance increases. A correlation is proposed to predict the average Nusselt number on the stagnation area for the heat sink with different structure parameters, and the deviations of predictions from the numerical results are less than 10%.