Pore-scale simulation of heat and mass transfer in deformable porous media

Abstract

Most porous media are susceptible to deformation during the heat and mass transfer process. In this paper, the bi-dispersed porous media model, which was generated through digitized image reconstruction, was used to effectively and conveniently simulate the real porous media. The thermal-hydro-mechanics model, which was established based on the Navier-Stokes equations and stress differential equations, was solved according to the finite element method. Meanwhile, the arbitrary Lagrange-Euler theory was applied to deal with the fluid-solid boundary. The results suggested favorable agreement between the numerical results and the experimental data. Moreover, the detailed distributions of velocity, temperature and water content in the porous media were obtained, which varied depending on the structural properties of porous media. Further, the stress and deformation were comparatively analyzed in the open and closed pore regions, and it was found that the wall of closed pore was prone to stress concentration. The deformation of the bi-dispersed porous sample resulted in an increase in pore area fractal dimension and a decrease in tortuosity fractal dimension. In addition, the effective transport properties and volume shrinkage of the deformable porous media at the representative elementary volume (REV) scale were also computed based on the obtained pore scale results, which confirmed that it was necessary to consider the effects of deformation on the real flexible porous media.