Lattice Boltzmann Simulation Of Seepage In The Two Dimensional Porous Media

Porous media is composed of solid skeleton and interconnected pores. The fluid flow through porous media is called seepage. In our daily life, the seepage in porous media is a common phenomenon in the exploitation of oil, natural gas, and water and other underground energy and resources, the prediction and prevention of natural disasters of ground subsidence and landslides. Therefore the analysis and research of the fluid flow through porous media have important scientific significance and application prospects.Because of the complex structure of porous media, the fluid velocity and direction change complicated when fluid flows through the porous media. It brings great challenges to the research of porous media seepage. For the classical numerical methods, although the macro simulation methods can represent the trend of flow of fluid, the macro simulation methods can not reflect internal flow detail about fluid; molecular dynamics simulation methods can well reflect the fluid details, but the method is limited by computer hardware. Therefore, many scholars have been working to find some more effective numerical simulation methods.In recent years, as a new numerical simulation method-the lattice Boltzmann method which has the features of clear physical meaning, easy to deal with complex boundary, simple programming and parallel, is widely used in the simulation of fluid flow through porous media. In this paper, the seepage of porous media is studied by the lattice Boltzmann method. In order to verify the validity and efficiency of the proposed method, numerical examples were carried out to examine the permeability with respect to the grid number, the boundary condition and the cell number, respectively. The numerical results show that, numerical simulation results are more and more accurate with refinement of grid. The result with fixed boundary is close to the reference solution than the result with periodic boundary. For the seepage of the porous media which is composed of regular-packed cylinder, a model with4cells can be chosen to study the seepage problem. Then, the fluid flow through porous media is studied by the codes based on the Lattice Boltzmann Method. Numerical results show that nonlinear phenomena appear in the seepage in porous media with the increase of flow velocity. At a high flow velocity, the Darcy’s law is no longer applicable, while the law of permeability with a nonlinear second order item can reasonably predict the permeability. Moreover, by simulating the flow in random porous media and porous media composed of regularly packed cylinders, it is found that the traditional empirical formula is more suitable to describe the seepage behavior in the porous media composed of regular-packed cylinders.