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.

Numerical Modeling of Pore Fluid Flow in Reconstructed Porous Media

In this paper, the numerical simulation of pore fluid flow in reconstructed porous media was carried out. The 3D porous computational domain was reconstructed based on the 2D images from micro CT scanner equipment. The Shan-Chen type lattice Boltzmann method (LBM) was adopted to establish the numerical model to predict the two-phase flow in the complex porous domain. The pore space is in micro/mini scale and the surface structure will have an influence on the pore fluid flow. Different surface tension coefficients were adopted in the numerical simulation to analyze its effect on the two-phase flow in complex porous media.