The Lattice Boltzmann Simulation Of Gas-solid Flow In A Driven Cavity

Gas-solid flow is a fundamental problem in the field of coal combustion. Lattice Boltzmann method (LBM) is developed rapidly in recent years as a new method of computational gas dynamics. Because of its microcosmic and mesoscopic properties of nature, the method to study gas-solid flow problems is a great advantage. In the LBM, the particles shape and movement can be visually described, so the phenomenon of particle collision, merger and fragmentation could be effectively interpreted. And the interaction between gas and particle can be well handled in LBM, Which is beneficial to carry out the coupling between particle dynamics and flow process from the microscopic point. However, some key issues need to be studied when we research the problems of gas-solid flow using the existing LBM. This paper focuses on study on gas-solid interaction which is ignored in the existing LBM. Specific works are:Firstly, we present, an extension of the lattice-Boltzmann-lattice-Gas method (LBM-LGA) proposed by Masselot and Chopard for gas-solid flows, in which the drag force between the gas and solid is considered.Secondly, the extended LBM-LGA method is applied to study the particle behaviors in a driven cavity flow and the effects of the stokers number, the total number and size of particles are analyzed using single-way method. The simulation results of one or lots of particles moving are qualitatively consistent with previous works. The results show that the time of mean square displacement(MSD) of particles cloud to reach extreme increasing as accretion of the stokes number and indicate particles cloud motion characteristics is nothing to do with the number and size of particles .Thirdly, the extended LBM-LGA method is applied to simulate driven flow containing fine particles and gas and explore a variety of factors which affect the gas-solid system. We can find that the change of mean square displacement and velocity and kinetic energy of gas increases with the increase of the Knudsen number, the Stokes number and particles number. In short, we present an extension of the lattice-Boltzmann-lattice-Gas method proposed by Masselot and Chopard and study the particle behaviors in a driven cavity flow. We explore a variety of factors which affect the gas-solid system using single-way and two-way coupling. The simulation results are qualitatively consistent with previous works and can be well explained using physical principle, which shows that proposed LBM-LGA method can serve as a promising tool for simulating gas-particle flows.