开孔泡沫金属传热和流动特性

Heat Transfer and Flow Characteristics of Open-cell Metal Foams

近年来开孔泡沫金属运用于散热设备逐渐成为研究的热点。由于开孔泡沫金属结构复杂无序,数值模拟时大都将其结构进行化简,目前已有种类繁多的简化模型,然而适用于其传热与流动特性模拟研究的简化模型尚不明确;另外,适用于散热领域的泡沫金属结构参数有待详细研究。为此,建立开孔泡沫金属的5种简化三维模型,并进行传热和流动特性的对比研究,认为Gibson-Ashby模型更能准确描述实际开孔泡沫金属的传热和流动性能。在此基础上,采用Gibson-Ashby模型对开孔泡沫金属的关键结构参数进行传热和流动综合性能分析,发现孔隙率90%、孔密度30PPI开孔泡沫金属翅片的综合性能j/f^(1/3)(j为换热因子,f为阻力因子)最优;将孔隙率90%、孔密度30PPI开孔泡沫金属翅片与平直翅片进行对比,发现开孔泡沫金属翅片换热效果是平直翅片的2倍以上,综合性能也优于平直翅片。所得研究成果可为开孔泡沫金属在换热领域的应用和设计提供参考。

In recent years,the application of open-cell metal foams in heat dissipation equipment has gradually become a research hotspot.Its structure is generally simplified in numerical simulation due to its complex and disordered structure.At present,there are a variety of simplified models,but the simplified models suitable for the simulation of heat transfer and flow characteristics are not clear.In addition,the structural parameters of metal foam suitable for heat dissipation need to be studied in detail.Therefore,five simplified 3-D models of open-cell metal foams are established,and the heat transfer and flow characteristics are compared to conclude that Gibson-Ashby model can describe the heat transfer and flow characteristics of open-cell metal foams more accurately.On this basis,Gibson-Ashby model is used to analyze the heat transfer and flow performance of open-cell metal foams.The results show that the comprehensive performance j/f^(1/3)of open-cell metal foam fins with 90%porosity and 30PPI pore density is the best.Comparing the open-cell metal foam fins with porosity of 90%and pore density of 30PPI with the flat fin,the results show that the heat transfer effect of open-cell metal foam fins is more than two times that of the flat fin,and its comprehensive performance is better than that of the flat fin.The research results can provide reference for the application and design of open-cell metal foams in heat transfer field.