SPH simulation of convection diffusion process in fractured porous media

To study the convection diffusion in fractured porous media, the Smooth Particle Hydrodynamics (SPH) method was applied to simulate the flow process of water at the pore scale level. The real migration process of solute penetrating fractured porous media was realized by simulation, and a simplified Two-Region Model was proposed to describe the penetrating process. In the calculation, the SPH method was first used to discretize the Navier-Stokes equation, and a two-dimensional hydrodynamic field model considering complex porous particle boundary was established. Based on the constructed model, simulation experiments of solute penetration of porous media with three different fracture widths were carried out. As the fracture width in the medium increased, the flow velocity difference between the fracture region and the matrix region increased, and the early penetration and tailing phenomenon became more obvious. The Two-Region Model could well describe this phenomenon, while the traditional convection diffusion equation could not, though it is difficult to obtain accurate analytical solutions from the generalized model. Therefore, a simplified method was proposed and its corresponding analytical solution was provided. Results show that the proposed model can fit to the breakthrough curves accurately in fractured porous media, and the parameters of convection dispersion can be obtained by inversion. © 2019, Editorial Board of Journal of Harbin Institute of Technology. All right reserved.