Optimal parameter design of a slot jet impingement/microchannel heat sink base on multi-objective optimization algorithm

Abstract

Jet impingement and microchannel cooling as effective cooling methods have been widely employed for thermal management of high heat flux electronics. In this work, a novel hybrid slot jet impingement/microchannel heat sink, combining the advantages of two cooling technologies, was proposed to achieve vertical flushing of the jet and timely discharge of the waste fluid. To further enhance the cooling performance, a 3-D numerical simulation was applied to evaluate the impact of inlet and outlet branch passage inclination ratios (Hin,1/Hin,2 and Hout,1/Hout,2), channel unit width (W1), channel width ratio (φ) and channel height (H3) on heat sink thermal-hydraulic characteristics. According to the parametric analysis, the variations in the inlet and outlet branch passage inclination ratios have significant effect on the mass flow distribution among the heat transfer channels. Afterward, to acquire the optimal compromise solution for practical applications, the artificial neural network training and multi-objective optimization algorithms, i.e. multi-objective particle swarm optimization (MOPSO) and multi-objective genetic algorithm (MOGA), are utilized to optimize the geometrical parameters, i.e. W1, φ and H3. During the optimization, the average heated surface temperature (T¯heat) and the total pressure drop (ΔP) are two conflicting objectives to evaluate the heat transfer and resistance characteristics. Finally, an optimal compromise solution (W1=1.03mm, φ=0.58 and H3=2.44mm) is chosen from the Pareto front by using the classical decision-making algorithm, i.e. TOPSIS. Compared with one objective minimization in the Pareto front, the optimal compromise solution has a sound balance between heat transfer and resistance performance. Additionally, for the optimal compromise solution, with an inlet velocity of 1.5 m/s and a heat flux of 200 W/cm2, the maximum and average temperature of the heated surface does not exceed 73 °C and 67 °C, respectively, and the total pressure drop is only 5.7 kPa.