Abstract:

The structures and the heat and mass transfer processes are complex and variable in porous media. Therefore, the further study should be taken on the precise analysis models for describing micro-pore distributions characteristics. Based on the concept of REV (representative elementary volume), two microphysical models for porous media (hollow skeleton primitive model, solid particle primitive model) were proposed. And the formulas for thermal conductivity calculation on two microphysical models were established respectively. In view of the micro-structure characteristics of porous media, the fractal method was used for fractal correction of these two primitive models, which was better represented micro-pore structures. Based on these models, the parameter influences on the thermal conductivity of porous media were analyzed by numerical simulation. The accuracy of the models were verified by the experiments of the self-developed experimental equipment.

Key words: porous media, heat conduction, characterization unit, transport processes, thermodynamic properties

摘要：

多孔介质内部组成结构复杂，热质传递过程多变，如何针对多孔介质的微观孔隙分布特性，建立更加精准的分析模型，有待深入研究。基于表征单元体（representative elementary volume，REV）概念，提出了孔隙型多孔介质的两种微观物理模型，即空心骨架基元模型和实心颗粒基元模型，分别建立了相应的热导率计算公式。针对孔隙内的微观结构特征，采用分形方法，对两种基元模型进行了分形修正，更好地表征了微观孔隙结构。基于所建模型，进行了模拟计算，探讨了相关参数对多孔介质导热特性的影响。通过自主研发的实验装置进行了相关实验，验证了模型的准确性。

关键词: 多孔介质, 热传导, 表征单元体, 传递过程, 热力学性质