结构参数对开孔泡沫传热特性影响的数值分析

Numerical Analysis of the Influence of Structural Parameters on Heat Transfer Characteristics of Open Cell Foam

为了解随机Kelvin cell结构的孔隙率和孔泡密度对泡沫材料内流体压降、体积对流换热系数和面积优度因子的影响,采用计算流体力学方法对不同孔隙率和孔泡密度的随机Kelvin ceil结构金属铝泡沫材料的强制对流换热(FCHT)过程进行了数值模拟。结果表明:入口速度在5~20 m/s范围内,当入口速度一定时,流体压降及体积对流换热系数随孔隙率的减小而增大,随孔泡密度的增大而增大;面积优度因子随孔隙率的增大而增大,随孔泡密度的减小而减小;入口速度在5~20 m/s范围内,面积优度因子在不同孔泡密度下随入口速度的变化具有不同的变化趋势,入口速度提高时,孔泡密度为5PPI的随机Kelvin cell泡沫面积优度因子呈增大趋势,孔泡密度为10PPI时面积优度因子呈先增大后减小趋势,孔泡密度为20PPI时面积优度因子呈减小趋势;压降及体积对流换热系数随入口速度的提高分别呈指数型、对数型增长。

To understand the impact of the porosity and pore density in random Kelvin cell structures on the fluid pressure drop,volumetric convection heat transfer coefficients and area optimization factor in foam materials,computational fluid dynamics(CFD)method was used to numerically simulate the forced convection heat transfer(FCHT)process in aluminum foam materials with various porosities and pore densities featuring random Kelvin cell structures.The findings indicate that within an inlet velocity range of 5-20 m/s,both fluid pressure drop and volumetric convection heat transfer coefficients increase as porosity decreases and pore density increases when the inlet velocity remains constant;additionally,the area optimization factor increases with the increase in porosity and decreases with the decrease in pore density.Within the inlet velocity range of 5-20 m/s,the trend of the area optimization factor varies with inlet velocity and pore density.As the inlet velocity increases,the area optimization factor for random Kelvin cell foam with a pore density of 5PPI increases,it first increases and then decreases for 10PPI,and it decreases for 20PPI.Both pressure drop and volumetric convection heat transfer coefficients exhibit exponential and logarithmic increases,respectively,with rising inlet velocities.