Shape Optimization of a Microchannel Heat Sink with Phase Change

Abstract

Optimization of a microchannel heat sink has been performed based on the analyses of fluid flow and heat transfer with phase change using three-dimensional Reynolds-averaged Navier-Stokes equations. The uniform heat flux condition is applied at the bottom of the heat sink. Three design variables, viz. ratio of microchannel width to height of the heat sink, ratio of fin height to heat sink height, and ratio of fin width to height of the heat sink are selected for the shape optimization. Latin hypercube sampling was used to determine the training points as a design of experiment, and the surrogate model is constructed using the objective function values at the training points. Sequential quadratic programming is used to search for the optimal point from the constructed surrogate model. The thermal resistance is set as the objective function. It was found that the thermal resistance increased with increasing ratios of the microchannel width-to-height of the heat sink and fin height to heat sink height, while the thermal resistance decreased with increasing ratio of the fin width-to-height of the heat sink. Through the optimization, the thermal resistance has been decreased by 37.3% compared to the reference geometry.