Impact of Size Distribution of Cell Model on the Effective Thermal Conductivity of Saturated Porous Media

Effective thermal conductivity of a porous medium is a key thermos-physical parameter in characterizing heat transfer properties in many applications. In this study, a new cell model to predict the porous medium effective thermal conductivity is developed by treating the cells as being variables in size in relation to porosity. In the new model, the interaction of a particle with the surrounding is conceptualized as a fluid cell surrounding the particle and the particle size distribution is explicitly taken into account by the variations of cell size in the porous medium. While the fluid volume fraction varies in different cells, the total fluid volume fraction in the porous medium is required to be the same as the porosity. The developed effective thermal conductivity model is then compared with experimental data sets from the literature. The effect of cell size variations on the effective thermal conductivity of porous medium is quantified and discussed. The results demonstrate that the model that incorporates cell size variations can capture scattered experimental data in the literature. The cell size variations significantly affect the effective thermal conductivity of porous medium and the non-uniformity of cell size enhances the effective thermal conductivity.