Heat transfer and fluid flow characteristics of a microchannel heat sink with microplates - A critical computational study

Abstract

High-performance and miniaturized modern electronic devices demand a high value of heat dissipation. The compactness of Microchannel Heat Sinks (MCHS) and other favourable characteristics, such as high surface area-to-volume ratios make them excellent candidates to dissipate high values of heat from small equipment footprints. As demonstrated in this study, incorporating micro-plates within the microchannel has been found effective for heat transfer enhancement. The present study investigates the effect of various numbers, sizes, and arrangements of micro-structures inside the microchannel heat sink using Open-FOAM, an FVM-based CFD package. The first analysis investigates the impact of introducing micro-plates, starting with larger micro-plates and then moving to smaller sizes. The heat transfer coefficient and pressure drop increase up to 27% and 49% respectively when two micro-plates are split into sixteen equal parts. In the second analysis, two micro-plates are removed at a time from the upstream and then from the downstream. It is found that the removal of plates reduces the heat transfer coefficient and this effect is more when plates are removed from the upstream as compared to removal from the downstream side. It is also found that the increase in plate length from 0.9375 mm to 1.875 mm increases the pressure drop up to 32% without affecting the heat transfer coefficient. In the final analysis, different arrangements of micro-plates with varying lengths are studied, and the effect on the microplate location and length is also critically investigated. The overall performance index of the microchannel configuration with sixteen microplates of length 0.9375 mm, is higher than all others. It is almost 11% higher than the microchannel with microplates of length 1.875 mm.