凹槽型微通道传热与流动性能的数值分析

针对电子器件的散热问题,提出了四种具有对称和等距凹槽的微通道,并通过三维数值模拟,研究了不同雷诺数下凹槽形状及布局对微通道性能的影响。结果表明:在给定的雷诺数范围内,圆形凹槽的传热性能仅次于三角凹槽,而梯形和矩形凹槽的传热性能较差。三角凹槽压降最大,其次是圆形,而梯形和矩形凹槽压降差异较小;同种形状不同布局的凹槽,压降几乎一致,这表明通过改变凹槽布局来提高性能不会产生额外压降损失。综合换热和压降特性,微通道热性能系数先增后减,故三角凹槽在雷诺数为600时获得最优热性能,而在雷诺数为900时等距圆形凹槽的热性能超过三角凹槽。

Numerical Analysis on Heat Transfer and Flow Characteristics of Grooved Microchannel

Four microchannel models with symmetrical and equidistant grooves are proposed for the heat dissipation of electronic devices. The effects of groove shape and layout on microchannel flow and heat transfer performance under different Reynolds numbers (R_e) were studied by three-dimensional numerical simulation. The results show heat transfer performance of circular groove is only inferior to that of the triangular groove, while trapezoid and rectangular grooves are poor. The pressure drop of triangular groove is the largest, followed by circular groove, and the pressure loss difference between trapezoid and rectangular groove is small, but the pressure drop is almost the same for the grooves with the same shape and different layout, which indicates that changing the groove layout to improve performance will not produce additional pressure loss. Combining with the characteristics of heat transfer and pressure drop, the thermal performance coefficient (TPC) of microchannel increases first and then decreases, so the optimal TPC is obtained with the triangular groove at R_e=600, while the TPC of the equidistant circular groove exceeds that of the triangular groove at R_e=900.