Estimation of the thermohydraulic performance of a microchannel heat sink with gradual and sudden variation of the flow passage

Abstract

Microchannel heat sink (MCHS) is used as an efficient method of thermal management in a miniaturized, high performance electronic devices. However, high pumping power and uneven distribution of temperature are two major limitations of such MCHS. In this work, efforts are made to optimize these limitations through modification of channel geometry. Three sequential computational analyses have been performed for a MCHS. In the first analysis, the channel cross-section reduces to a minimum one (at the throat) and then increases. For five different throat positions are considered for this analysis. None of the channel configuration achieves the overall performance more than 1. Next, sudden contraction and expansion are introduced in the channel passage. Three different cross-sections are used. The sudden expansion recovers the pressure gradually, whereas, at sudden contraction, the pressure drops instantaneously. The overall performance index (OPI) improves when two channel sections with larger cross-sectional area is connected by a channel with smaller cross-section. The OPI of such configuration is found to be greater than 1. Finally, multiple sudden expansion and sudden contraction are introduced sequentially in the channel cross-section. It is observed that the heat transfer performance and pressure drop both increases with increase in number of expansion and contraction.