Hydrothermal performances of symmetric and asymmetric divergent-convergent microchannel heat sinks

摘要

The present work numerically studied the hydrothermal performance of symmetric and asymmetric divergent-convergent microchannel heat sink (DCMCHS) with the rectangular cross-section. Three different DCMCHS with fixed total channel volume were designed, the symmetric DCMCHS, the width-asymmetric DCMCHS with the fixed inlet-to-middle cross-sectional width ratio, and the width-asymmetric DCMCHS with the fixed middle cross-sectional width. Effects of the inlet-to-middle cross-sectional width ratio and channel height of the symmetric DCMCHS, and the outlet-to-inlet width ratio, the middle cross-sectional width and the channel height of the width-asymmetric DCMCHSs on the maximum temperature, overall thermal resistance, pressure drop, and the coefficient of performance {COP) of the DCMCHSs were analyzed. It was found that the symmetric DCMCHS with smaller inlet-to-middle width ratio has smaller thermal resistance but larger pressure drop. Moreover, the decreasing outlet-to-inlet width ratio can improve the thermal performance of the two width-asymmetric DCMCHSs and increase the pressure drop. The increasing middle cross-sectional width can reduce the thermal resistance of width-asymmetric DCMCHS with fixed channel height and fixed outlet-to-inlet width ratio by consuming more pressure drop. For the COP, all the proposed DCMCHSs in the present work have smaller COP compared with the conventional parallel MCHS.