Algorithm Study For Heat And Mass Transfer In Porous Media

Whether the exploitation of oil and natural gas hydrate, or the design of the fuel cell, also, or the development of the fibrous porous materials. They are both related to the heat and mass transfer in porous media. Given the complexity of the porous media fluid flow and heat transfer, researchers are actively seeking suitable ways and means to solve this kind of problem.With the rapid development of computer, We can understand the complex behavior of fluids in porous media by simulation. Before the computer numerical simulation, we first have to model a physical process, it means to use appropriate mathematical equations to describe the problem, such as oil exploitation. In modeling heat and mass transfer behavior in porous media, we found that many of the physical processes are inseparable from the solving of the source term, source term has an important role in the achievement of the physical field coupling, therefore, the solving of the source term problem is one of the key points of the entire simulation. We need to design a better method to adapt source term problem solving.In addition, in the field of engineering applications, in the stage of theoretical analysis, generally requires combination of direct and inverse analysis, by simultaneous using the direct and inverse method to better guide the practical development. We often encounter these two cases:known the material parameters but unknown the total heat transmission or the temperature field during the heat transfer process; known the total heat transmission or the temperature field during the heat transfer process but the material parameters are unknown. The above two cases corresponding to the direct analysis and the inverse analysis, respectively. Direct problem can be modeled by mathematical equations, thus in direct problem, the solutions are obtained by solving the corresponding mathematical equations. Meanwhile, there’s no appropriate mathematical equations to describe the inverse problem, therefore, their solutions require some kind of optimization algorithm.After the above analysis, we recognize that whether the solving of the source term problem, or the solutions of the direct and inverse problems, we must design a suitable algorithm. Because of its efficiency to solve the problem of heat and mass transfer, lattice Boltzmann method and finite volume method have been widely used in engineering fields. Genetic algorithm is based on the idea of survival of fittest during the biological evolution, it has been widely used in the optimization field.In our paper, firstly, we introduced the significance of the algorithm study of heat and mass transfer in porous media, describing the main idea of the lattice Boltzmann method, the finite volume method and genetic algorithm. Secondly, based on the natural convection in porous cavity, we described the recovery of the mass and momentum equations based on the D2Q9model and the discrete of energy equation based on the control volume. Achieving the coupling of the velocity field and temperature field, constructing a multi-scale numerical simulation method to adapt the solving of source term problems. Thirdly, based on the conductive and radiative heat transfer in fibrous porous materials, we described the discrete of the conductive and radiative heat transfer equations by the control volume and mid-point quadrature formula, then, we introduced the corresponding implementation, completed the solving of the direct and inverse problem. The last but not the least, we introduced our two studies:simulation of natural convection heat transfer problem in porous medium based on the lattice boltzmann method with the finite volume method; recovery of the porosity (porosity seed) based on the finite volume method with the genetic algorithm.