Abstract The microstructures of porous alumina materials with different porosities were established by introducing the departure factor of pore position and acentric factor of pore diameter to describe the distribution of pores in space and in size, respectively. The contribution of radiation and influence of pore distribution on the equivalent thermal conductivity were discussed based on numerical simulations by the finite volume method (FVM) considering both thermal conduction and radiation. When the pore diameter was less than 10 µm, the radiation component was less than 2%, and radiation could be neglected. Radiative heat transfer played a dominant role for materials with high porosity and large pore size at high temperatures. For micro pore materials ( 1 mm), broad pore distribution decreased the thermal conductivity at low temperatures and increased it at high temperatures. The basic prediction model of effective thermal conductivity for a two-component material, the Maxwell–Eucken model (ME1) and its modified model were corrected by introducing the pore structure factor. The results from experiments prove that the numerical values were satisfactory.

中文翻译：

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孔隙分布对低孔隙率陶瓷闭孔泡沫等效热导率的影响

摘要 通过引入孔隙位置偏离因子和孔径偏心因子分别描述孔隙在空间和尺寸上的分布，建立了不同孔隙率的多孔氧化铝材料的微观结构。基于热传导和辐射的有限体积法（FVM）数值模拟，讨论了辐射的贡献和孔隙分布对等效热导率的影响。当孔径小于10μm时，辐射成分小于2%，辐射可以忽略不计。辐射传热对高温下孔隙率高、孔径大的材料起主导作用。对于微孔材料（1mm），宽的孔分布在低温下降低了热导率并在高温下增加了热导率。通过引入孔隙结构因子对双组分材料有效导热系数的基本预测模型 Maxwell-Eucken 模型 (ME1) 及其修正模型进行了修正。实验结果证明数值是令人满意的。