Lattice Boltzmann Method For Heat And Mass Transfer Problems Involving Liquid-Solid Phase Change

Phase change is a typical case of heat and mass transfer. And substance change phase with porous media is very common in industrial production and daily life. In recent years, in order to enhance the heat transfer coefficient, phase change materials are filled with porous medium. The melting process research is vital for mining natural gas hydrate. The reserve of natural gas hydrate is very rich. The energy mainly exists in permafrost, which can be transformed into natural gas and water by the hot-water injection method exploitation. Owing to the nonlinear characteristics of phase change problems, we need an efficient and reliable numerical method to deal with it.After several decades' development, Lattice Boltzmann method (LBM) as a emerging numerical method has become a new tool for simulating fluids flow and modeling complicated physical phenomena. The method is widely used in the macroscopical fluid systems of aviation, energy exploitation, environment project. Unlike the traditional Computational Fluid Dynamics (CFD) methods, LBM is not based on macroscopic continuum equations, but microscopic model and mesoscopic kinetics equations. Then, according to certain physical rules, we construct the evolutionary mechanism to calculate and simulate macro flow field. Compared with the traditional CFD methods using Navier-Stokes equations, LBM has many unique advantages, such as simple codes, easy implementation of boundary conditions, and fully parallelism. These features make LBM apply successfully to many fields, especially for heat and mass transfer in porous media. In this thesis, LBM is used to simulate pure phase change process and phase change with convection in porous media, and some useful discussions are also given here.In this paper, a comprehensive introduction of the research significance and recent studies of convection heat transfer in porous media are given. What's more, we especially introduce the basic concepts and macroscopic governing equations for convection heat transfer in porous media here. Then we introduce the basic concept and research significance of phase change, and concretely analyses the phase transition process of the heat conduction and the phase transition with convection to draw the macroscopic equations and Lattice Boltzmann equations. By researching, we innovatively puts forward the migration-collision scheme of Lattice Boltzmann method, and presents its superiority on handling phase change problem through concrete analysis and numerical simulation. Lastly, phase-change process with convection in porous medium is simulated by Lattice Boltzmann method. The macroscopic equations and Lattice Boltzmann equations are also proposed. Then a two-dimensional model is founded to consider the parameters of phase-change process with convection in porous medium.