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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 numerical methods are used to solve the gas-phase and solid-state heat transfer processes of a variety of three-dimensional ordered porous materials at room temperature. The effective thermal conductivities of the materials with different structures are obtained. The obtained effective thermal conductivities are low when the material density is low At 170 kg / m, it is in good agreement with the experimental results. The coupling heat transfer model of water vapor adsorbed on porous materials was established. The influence of water vapor adsorption on the effective thermal conductivity of silica aerogels was studied. The results showed that the moisture content of silica aerogels increased by 1% , Will increase its effective thermal conductivity, the increase of about 2% of the thermal conductivity of the material solid phase.