新型金属泡沫-微柱群复合热沉内流动传热性能分析

Thermo-hydraulic performance analysis of novel metal foam and pin fin hybrid heat sink

高效热管理技术是大功率微电子设备安全运行的可靠保障。为进一步强化高功率电子器件的冷却效果,本文提出了一种新型泡沫铝-微柱群复合热沉结构。采用实验和数值模拟相结合的方法对新型水冷泡沫铝-微柱群复合热沉内的流场分布、壁面温度分布、阻力系数、换热性能及柱鳍与泡沫铝间的耦合传热规律等开展了深入分析。研究结果表明,与传统微柱群热沉相比,20PPI泡沫铝-微柱群复合热沉的壁面最高温度大幅降低,平均换热性能提升了33.9%~41.5%。然而,微柱群内填充泡沫铝却导致流动阻力增大,增加了7.9~10.5倍。泡沫铝-微柱群复合热沉的强化换热机理为:微柱群热沉内填充高热导率泡沫铝提升了热沉整体的有效导热性能,热量可通过金属泡沫固体骨架迅速传递,同时多孔界面较强的传热能力能够保证热量及时被冷却流体散除。本文相关研究成果可为高热流密度电子器件散热装置的研发提供理论指导。

Efficient thermal management technology is imperative for the normal operation of highpowered electronic devices.In this paper,a novel aluminum foam and pin fin hybrid heat sink(AFPFH heat sink)was proposed to further enhance the cooling performance.A combined experimental and numerical study was conducted to investigate fluid flow and heat transfer characteristics of AFPFH heat sink subjected to forced water flow.The streamline distributions,temperature distributions,friction factors,heat transfer performances,and conjugate heat transfer characteristics between pin fin and metal foam were presented.Results showed that the bottom wall temperature of AFPFH heat sink was significantly reduced in comparison to the traditional pin fin heat sink,and the average Nusselt number was improved by 33.9%—41.5%.However,the deduced flow resistance was increased by approximately7.9—10.5 times.The heat transfer augmentation mechanism of AFPFH heat sink was that the addition of high thermal conductivity aluminum foam into pin fin heat sink enhanced overall effective thermal conductivity,which improved conductive heat transfer through the metal foam ligaments.Meantime,the superior convective heat transfer capability at the porous interfaces promoted heat dissipation by the cooling fluid.The present results could provide a theoretical guideline for the development of efficient cooling alternatives for electronic devices.