Multi-objective optimization on thermal–hydraulic performance of symmetrical hierarchical microchannel heat sinks

Abstract

The increasing integration of microelectronic devices will lead to hot spots and reduce service life. The microchannel heat sink can effectively manage thermal loads, and its energy efficiency requires urgent enhancement amidst global energy constraints. This study investigated the effects of the secondary channel width and trapezoidal bottom angle on the thermohydraulic performance through numerical simulation and multi-objective optimization. Results showed that expanding the secondary channel width provides a larger flow space and increases the heat transfer area. The pressure drop is reduced, while maintaining effective cooling. The energy efficiency ratio of the cooling system is improved. Increasing the trapezoidal bottom angle can increase the velocity and takes away the heat quickly. The temperature uniformity is improved to avoid excessive local hot spot. Taking the minimization of pressure drop and thermal resistance as objectives, the Pareto optimal solution is obtained by Non-dominated Sorting Genetic Algorithm II. Using Technique for Order Preference by Similarity to Ideal Solution with entropy weight to get the optimal compromise solution. The secondary channel width is 0.216 mm, and the trapezoidal bottom angle is 56.93°. Compared with the microchannel without fins, the pressure drop is reduced by 15.19 % and the thermal resistance is reduced by 23.79 %. A new method was provided to improve the efficiency of structural optimization and obtain microchannel structures with high temperature uniformity and energy efficiency ratio, which provides a very important reference value for the parameter optimization of microchannels.