多孔铝内体积对流传热系数的测量

引　言多孔铝 (合金 )作为一种高孔隙率 (孔隙率 >0 9)多孔介质 ,具有明显的多功能性[1] .通孔型多孔铝是指多孔铝的内部孔隙互相连通 ,且外部流体可以通过 ,具有比表面积大、质量轻的特点 ,是开发强化换热装置的优选材料 ,有可能在新型紧凑式换热器、回热器、风冷冷凝器 (或冷却塔 )等换热设备研制过程中获得应用 .但流体流经多孔铝的　对流换热特性实验数据比较缺乏 ,对各种影响因素的研究也欠充分 .Hwang等[2 ] 测量了空气流经70 %、 80 %、 95 %三种孔隙率多孔铝的体积对流传热系数 ,但缺乏对孔隙密度、母材性质等影响的研究 .何德坪…

MEASUREMENT OF VOLUMETRIC CONVECTIVE HEAT TRANSFER COEFFICIENT IN POROUS ALUMINUM

Although forced convection in porous media has been studied for many years, there are only relatively few investigations of convective heat transfer in porous metal with porosity higher than 0.9.This paper reports an experimental study on convective heat transfer and pressure drop in high porosity porous aluminum.Four typical samples with the same porosity 0.92 but different pore density (10 PPI and 20 PPI) or material (A356 Al alloy and 6101 Al alloy) were used in the test.In order to measure volumetric convective heat transfer coefficient of air flowing in the samples, a single blow mathematical model was developed and the experimental setup was built.The air frontal velocity was located in 0.6 m•s^-1 to 2.6 m•s^-1.The effects of pore density and material on the heat transfer and pressure drop characteristics were discussed.The results showed that pore density affected the heat transfer coefficient and pressure drop drastically while the effect of material (and manufacture) was quite different for different pore densities.More work is to be done on the relations between the microstructure and the macro heat transfer performance of porous aluminum.