Optimal shape design of a minichannel heat sink applying multi-objective optimization algorithm and three-dimensional numerical method

In the present study, an optimal laminar flow minichannel heat sink (MCHS) has been determined through three-dimensional simulations and the multi-objective optimization algorithm. The cross-sectional shape described by six variables is optimized by the multi-objective genetic algorithm (MOGA) and multi-objective particle swarm optimization (MOPSO). During the optimization, the thermal resistance theta and pumping power P are two conflicting objectives for evaluating the performances of the MCHS. After obtaining the non-inferior solutions, the technique for order preference by similarity to an ideal solution (TOPSIS) is applied as a decision-making method to determine the best compromise one. Results indicate that the TOPSIS can effectively reduce the P of the Pareto solutions without significantly increasing theta. Compared with the straight channel, the TOPSIS optimal solution could reduce theta by 7.47% or P by 31.54%. Meanwhile, the mechanism of performance improvement is analyzed by comparing the TOPSIS optimal solution and the straight channel with the same P. It is observed that the optimized channel shape changes the fluid distribution by increasing the heat transfer coefficient slightly and the heat transfer area by 12.22%, respectively.