纳米多孔材料有效热导率数值研究

Numerical Study on Effective Thermal Conductivity of the Nanoporous Media

通过数值方法对多种三维有序结构多孔材料在常温条件下的气相、固相导热过程进行耦合求解,获得了不同结构的材料的有效热导率,所获得的有效热导率在材料密度低于170 kg/m时,与实验结果符合较好。建立了多孔材料吸附水蒸气的耦合传热模型,研究了水蒸气的吸附量对二氧化硅气凝胶有效热导率的影响规律,结果表明:二氧化硅气凝胶含湿率增加1%,会使其有效热导率增加,其增幅约为材料固相热导率的2%。

The conjugate heat transfer of the gas and solid phase in the nanoporous media with various three dimensional ordered structures was numerically solved.The obtained results for the effective thermal conductivity are in good agreement with the experimental data when the density of the porous media is less than 170 kg/m3.Heat transfer coupling model considering the moisture content in porous material was established as well.We studied the effect of the moisture content on the effective thermal conductivity of the silica aerogel,and the results show that the effective thermal conductivity gains an average increase in 2%of the solid thermal conductivity for 1%increase in the moisture content of the porous material.