Multi-objective optimization of a hybrid microchannel heat sink combining manifold concept with secondary channels

•A novel optimization approach is proposed to optimize the performance of a hybrid heat sink.•The Pareto-optimal set is obtained and verified by CFD results.•The optimized heat sink can reduce thermal resistance by 18.83% compared with manifold heat sink.•TOPSIS with entropy weight method is applied to select the best compromise solution from Pareto-optimal set. A novel optimization approach, which combines optimal Latin hypercube design (Opt LHD), Pareto chart analysis, response surface methodology (RSM), the non-dominated sorting genetic algorithm II (NSGA-II) and technique for order preference by similarity ideal solution (TOPSIS), has been proposed and applied to optimize the performance of a hybrid microchannel heat sink combining manifold concept with secondary oblique channels. Four geometric parameters are selected as design variables and the optimization objective is to minimize the total thermal resistance Rt and pumping power Pp simultaneously. First, 160 sample points is generated by Opt LHD and the Pareto chart analysis is performed to identify the dominant design parameters influencing the objectives. Then, RSM is used to generate approximate models relating to the objectives and design parameters, and NSGA-II is selected to minimize Rt and Pp. 374 Pareto-optimal solutions are obtained and verified by CFD results, which indicates that the hybrid design can reduce Rt by 18.83% compared with manifold microchannel heat sink under the same Pp. Finally, the best compromise solution is obtained by TOPSIS combined with entropy weight method. The proposed optimization approach can also be applied to optimize the performance of other types of heat sinks.