Optimization of a stacked microchannel heat sink using nanofluids (AL2O3-H2O) with multiobjective optimization of thermal resistance and pressure drop

The single layer microchannel heat sink (MCHS) introduced a decade ago in microelectronics systems (MEMS) may no longer be an adequate solution. Possible extension of the layer of microchannels into a stacked system, by developing a multi-layer channel system, is investigated. The objectives of this study are to develop modified mathematical models for stacked (multi-layer) MCHS, using water and nanofluid of alumina-water based (Al
₂
O
₃
-H
₂
O), at volumetric fraction (φ) of 1%, 2.5%, and 5 %, for channel height of 287 μm, finally, to optimize the thermal and hydrodynamic performance of the proposed model. The results of the optimization were carried out by multiobjective genetic algorithm, MOGA. The optimized thermal resistant and corresponding pressure drop, showed that at a channel height of 287 μm and at volume fraction φ =5% water based alumina nanofluid provided the lowest value of the thermal resistance of 0.0282 “L/W for a multi-stacked (five layers) MCHS with pressure drop of 58.9 kPa as compared to 0.0867 C/W and 261.8 kPa for a single-layer MCHS at an optimum value for $a (channel height to channel width) and β (wall width to channel width) of 6.5 and 0.99 respectively.