波纹壁树状微通道圆盘热沉的构形设计

Constructal design of tree-shaped microchannel disc heat sink with wavy walls

[目的]为了满足船舶与水下航行器等对电子器件高效热管理的需求,开展波纹壁树状微通道圆盘热沉的构形设计研究。[方法]提出波纹壁树状微通道圆盘热沉的设计原型,基于构形理论,在给定热沉体积和液冷微通道体积的约束条件下,以综合考虑传热和流动压降的复合性能指标(PEC)最大化为目标,对波纹壁的振幅和波长进行构形设计。[结果]结果表明:与直通道热沉相比,波纹壁能增大换热表面积,且凹穴处能够产生涡,因而能够有效降低最高温度。当入口雷诺数为700,900或1100,增大波纹壁的振幅时,热沉最高温度降低了13.5 K,但是压降损失明显增大;减小波纹壁的波长,热沉最高温度降低了4.7 K,压降损失增幅较小;在给定波长较大时,均存在最优振幅使复合性能指标取得极大值;在给定波长较小时,随着振幅的增加,复合性能指标单调递增。[结论]波纹壁能够显著提升树状微通道圆盘热沉的传热性能。通过构形设计能够获得复合性能最佳的最优几何结构。

[Objective]To meet the efficient thermal management needs of electronic devices such as ships and underwater vehicles,this study focuses on the constructal design of a tree-shaped microchannel disc heat sink with wavy walls.[Method]A design prototype of the heat sink with wavy walls is first proposed.Based on constructal theory,the amplitude and wavelength of the wavy walls are designed under the constraints of fixed heat sink volume and fixed microchannel volume by maximizing the comprehensive performance evaluation criteria(PEC)while considering both heat transfer and flow pressure drop.[Results]The results show that the wavy walls increase the heat transfer surface areas and generate vortices in their cavities,effectively reducing the maximum temperature.When the inlet Reynolds number is fixed at 700,900 or 1100 respectively,the maximum temperature is reduced by 13.5 K by increasing the amplitude of the wavy walls,while the pressure drop increases significantly;and the maximum temperature is reduced by 4.7 K by reducing the wavelength of the wavy walls,while the pressure drop increases slightly.There are optimal amplitudes that raise the comprehensive performance evaluation criteria to extreme values for given larger wavelengths,while the comprehensive performance evaluation criteria increase monotonously as the amplitude increases for given smaller wavelengths.[Conclusion]Wavy walls can significantly improve the thermal performance of tree-shaped microchannel disc heat sinks,and the use of constructal design can realize optimal geometric constructs with optimal comprehensive performance evaluation criteria.