MULTISCALE MODELING OF FLOW AND HEAT TRANSFER IN POROUS MEDIA

A great number of studies have been carried out to provide the macroscopic descriptions of the overall viscous resistance and heat transfer in the porous media. The new numerical study is necessary to be performed to obtain an understanding of the characteristics at macro/pore scale. The multiscale modeling of the flow and heat transfer in the porous media remains difficult with standard one mesh methods due to the heterogeneity in different scales. In this study, the convection heat transfer is simulated using a macro-scale model including the thermal non-equilibrium assumption. The results, which are validated by the predictions in open literature, show that the convection heat transfer in the porous media can be predicted numerically using a thermal non-equilibrium model. To understand the heat transfer characteristics between the fluid and the solid in porous media, a pore-scale model is developed to obtain the macroscopic properties, especially the convective heat transfer coefficient between two phases. A single cell is simulated to represent a small region in a much larger porous medium. The complex porous structure is reconstructed based on the review of the previous studies and the computational fluid dynamic technique is used to predict flow and heat transfer process. The present work can be extended to study the phase change phenomena in complex structured media, which is normally applied in the latent heat thermal energy storage.