Multi-objective optimization of water-cooled pinfin heatsinks

This paper presents the multi-objective optimization of water-cooled pinfin heatsinks. The heat transfer rate and pressure drop were the objective functions, and four parameters (height, diameter, longitudinal pitch, and transverse pitch) of pinfin geometry were the design variables. The relationship between the objective functions and the design variables for pinfin heatsink was calculated by using our own semi-analytical equations. We applied two kinds of constraints. One is the clearance distance between the tip of the pins and the flow channel wall, and the other is the minimum gap between pins considering cost-effectiveness and manufacturability. The best trade-off curves between the pressure drop and the heat transfer rate were calculated using genetic algorithm. We found the similarity of the best trade-off curves under two different constraint conditions when the multiplication of the pin height and the minimum gap between pins were the same. We also showed that the small clearance causes the reduction of pressure drop while maintaining high heat transfer performance. Our calculated solutions were validated by comparing with experimental results. The pressure drops could be predicted within an error of 30%, and the effective heat transfer rates agreed within an error of 10%.