Optimization of a double-layered microchannel heat sink with semi-porous-ribs by multi-objective genetic algorithm

Thermal resistance and pumping power are two key metrics to evaluate the performance of microchannel heat sinks. To reach their better performance, porous medium can serve as an appropriate alternative to conventional solid rib due to its unique geometric architecture. In this work, the performance of a selected porous-ribs microchannel heat sink proposed previously is significantly improved through a 3D fluid-solid conjugated model coupled with a multi-objective and multi-parameter genetic algorithm optimization method. The optimal design and operation parameters are achieved under a constant volumetric flow rate. The Pareto-optimal front presents that the MCHS can reach a minimum thermal resistance of 0.06306 K/W with pumping power of 0.38317 W, and a minimum pumping power of 0.00171 W with thermal resistance of 0.37755 K/W. The optimization finds the optimal thermal resistance and pumping power are 0.09348 K/W and 0.02888 W, respectively. It shows that not only the cooling performance is significantly improved by 14.06%, but also the pumping power is considerably reduced by 16.40% when compared with the original design. Furthermore, the underlying physics of the effect of multi-parameter on the performance is analyzed. The results reveal that the compromise mediation between the pumping power of the upper channel and the cooling performance of the lower channel is responsible for reaching the optimal performance. Based on this mechanism, the design criteria to reach performance of preference are proposed. (C) 2019 Elsevier Ltd. All rights reserved.