Parallel Two-phase Flow Simulations And Its Implications Using The Lattice Boltzmann Method

Two-phase flow in porous media, always the worldwide research focus, plays a significant role in a range of technological and environmental fields. Especially in the recent years, with the development of environmental geotechnical engineering, the improvement of two-phase flow system is accelerated by the prediction of groundwater contamination and underground engineering practice,which raise more requirement of the flow system. All in all, the research of two-phase flow in porous media has both highly theoretical sense and realistic sense.In the last two decades the lattice Boltzmann method (LBM) has matured as an alternative and efficient numerical scheme for the simulation of fluid flows both in its theory and application. The lattice Boltzmann model is based on the statistical physics and describes the microscopic behavior of particles in a very simplified manner, but on the macroscopic level it gives correct average values for velocity, density, pressure and for other characteristics of flows. Thus it has the advantage of both microscopic and macroscopic models, and it is used to solve the problem that is hard to answer by traditional simulation models.However, the increasing scale of the problem and number of lattice is challenging the calculation ability. Therefore, it is urgent to solve the problem with more powerful computer systems and techniques. Parallel computers and parallel algorithm emerged to provide us with a high-speed calculation. For now, lattice Boltzmann method parallelism and scalability advantages have been fully reflected.We discuss the parallel implementation using LBM method under RedHat Linux environment. Based on Fortran and MPI, we workout the normal LBM parallel process, which is verified by simulating two-dimension Poseuille flow and comparing the results of numerical experiments to the theorical results. By introducing physical forces between the molecules, the parallel algorithm of two-phase flow is designed. And the implementation through several idealized numerical experiments, the results of which have been shown by laboratory measurements or are known from theory, shows the validity of that parallel process for physical two-phase flow in porous media. Application of the method to fluid intrusion in porous is discussed and shows the effect of wettability on the fluid flow. The capability of reproducing critical flooding phenomena under strong wettability conditions is also proved.