The Lattice Boltzmann Simulation Of Particle Transport In A Square Cavity With Natural Convection

Particle transport in fluids is a typical multi-phase issue, and it appears in many natural and industrial process, such as the frequent haze, the motion of coal particles in fluidize bed and the dust removal system of flue gas etc. Due to the more and more serious particle pollution in the air in our country, it is of great importance to study how the particle transports in the air. With the rapid development of computer technology, numerical simulation has become an important means to study the gas-particle flow. And as a recently developed numerical method, the lattice Boltzmann method(LBM) has many advantages compared to the traditional method. So it's widely used in the gas-particle simulation. The issue of gas particle flow has been studied by many researchers, however, most of them focus on the isothermal fluid. And study on the particle transport in fluid with temperature gradient is much less. In this paper, the particle transport in non-isothermal fluid will be studied with the Lattice Boltzmann Method.Firstly, the LBM with Lagrangian tracking method is used to simulate the particle transport in a square cavity, and the results are compared to previous work. A good agreement was gotten in the paper. Secondly, the particle transport in a square free convection is studied. The results show that a fraction of particles were trapped in a quasi-steady recirculation zone for a low Rayleigh number. And the particle diameter has a significant effect on the motion of particles. With an increasing Rayleigh number, the effect of particle diameter decreases. When the Rayleigh number increases to a critical value 6×105,the effect of particle diameter can be ignored. Our results also confirm the importance of the thermophoresis and the Brownian dispersion. Lastly, the particle transport in a cavity with internal heaters and coolers is numerically investigated. The results indicate that the particle distribution is strongly non-uniform at low Rayleigh number. Moreover, it is observed that the deposition rate of the particles increases as the number of the hearters and coolers increases or the orientation of heaters and coolers changes from vertical to horizontal.