Lattice Boltzmann simulation of complex fluid systems in porous media.

摘要

Lattice Boltzmann (LB) method is a promising technique for modeling fluid flow in complex systems. It is a novel approach with many advantages, such as the simplicity of its extension to three dimensions and its inherent treatment of complex systems.; The purpose of this dissertation is to implement the LB method to simulate single and two-component fluid flow inside porous media. A novel technique to generate porous media has been developed using fractals. The single component flow includes implementating the LB method inside two-dimensional and three-dimensional porous media. The two-component model includes a two-component flow inside a two-dimensional porous medium. The validation of our single component LB model against a benchmark problem of fluid flow inside an empty duct showed that the deviation between two techniques is less than 2% for three-dimensional flow. Also, for a two-dimensional case, our LB model and the analytical solution fit precisely when using a no-slip boundary condition. The LB model single component flow calculations agreed with Darcy's Law for fine and mid-coarse porous media. However, the two models (i.e., LB model and Darcy's Law) deviated when applied to a coarse porous medium. For a two-component flow, the LB model showed an agreement with Laplace's Law.; On the other hand, the two-component model simulated different stages of the Rayleigh-Taylor (RT) instability, such as linear growth of the interface, developing of spikes and bubbles, and the Kelvin Helmholtz (KH) instability. The RT instability suffered from diffusibility during the late stage of simulation. The RT instability was modelled inside a porous medium where heavy and light fluids were displaced. This dissertation presents the basic concepts which enable different studies to be performed for two-component flow and fluid flow in porous media.