Pore-Scale Modeling of Natural Convection in Reconstructed Porous Media

The utilization of porous media can enhance the heat transfer process due to its large heat transfer area within limited space. The natural convection in porous media widely exists in various heat transfer equipment and the related flow and heat transfer in porous spaces is one complicated transport phenomenon, for which the accurate prediction is challenging. Pore-scale models can predict transport phenomena in porous media in pore space, which can be used in the modeling of flow and heat transfer in porous media under local thermal non-equilibrium condition. The pore-scale study includes the reconstruction of porous structure and the direct numerical simulation of transport phenomena in the pore spaces. In this paper, the geometrical reconstruction approach was developed to generate the porous region using the tomographic reconstruction, which is one nondestructive imaging technique. The porous sample was scanned on a micro-CT scanner with micrometer resolution. 2D sliced scan images were obtained and then stacked to reconstruct the 3D porous geometry. A double-population thermal lattice Boltzmann model was established to predict the natural convection in reconstructed porous media at pore scale.