Fractal Analysis of Thermal Conductivity of Unsaturated Porous Media With Rough Surfaces

The effective thermal conductivity of rough porous media plays an important role in many heat transfer projects. But the roughness of pore surface in porous media is often ignored in traditional research. Based on the thermoelectric similarity theory and considering the statistical self-similarity characteristics of the internal structure and pore surface structure of porous media, a fractal model of thermal conductivity in unsaturated porous media with a rough surface is established, and the influence mechanism of porous media structural parameters, such as porosity, roughness and liquid saturation on effective thermal conductivity is analyzed in detail. The theoretical results are consistent with available experimental data, which verifies the correctness of the model. In addition, it is found that the effective thermal conductivity increases with the increase of liquid saturation and decreases with the increase of relative roughness. This model has no empirical parameters, and each parameter has clear physical significance. The thermal conductivity model proposed in this paper can be extended to predict the thermal transport properties of fractal porous media. © 2023 Science Press. All rights reserved.