Numerical investigation on hydrothermal performance of microchannel heat sink with impingement jet inlet arrays

Jet impingement has been introduced in the microchannels for improving overall thermal performance of heat sink. In previous literature, the jet impingement usually exerts its effect outside of the microchannels and there are no direct comparative studies about the microchannels with center and conventional inlets. In this paper, the jet impingement is designed directly in the center of the micrometer-scale microchannels, and exerts its extremely-efficient heat dissipation in narrow microchannels. Therefore, the microchannel and jet impingement are combined to form a new efficient heat dissipation system for high-power chip cooling. In the hybrid jet impingement/microchannel heat sink (JMCHS), an array of jet nozzles are set in the center region of the microchannel cover, and two outlets are located on both sides of each microchannel. Its comprehensive heat transfer and flow performance is analyzed by simulation and compared with the conventional microchannel (CMC) without jet impingement. The results show that the Nusselt number and average heat transfer coefficient of jet microchannels (JMCs) are all larger than that of CMC, and the maximal Nusselt number and average heat transfer coefficient of the JMC with lj = 300 mu m are both 28.9 % higher than those of CMC. With the same flow quantity, the pressure drop of all JMCs are drastically reduces due to the implementation of more channels and outlets for fluid flow. When Re = 1000, the reduction of pressure drop has reached 67.1 %. These imply the proposed JMCHS not only can enhance the heat transfer by the introduction of jet impingement, but also significantly reduces pressure drop penalty. Furthermore, the reduced nozzle size can slightly increase the heat dissipation capacity and pressure drop penalty of the proposed JMCHS.