Numerical investigation of dispersed gas-solid two-phase flow around a circular cylinder using lattice Boltzmann method

摘要

The vortex structures and particle dispersions in flows around a circular cylinder are investigated by lattice Boltzmann method (LBM), with non-equilibrium extrapolation method (NEM) dealing with the computational boundaries. The particles are traced in the Lagrangian framework. The effect of the Reynolds number (Re = 40-100) on the evolution of the vortex structures is investigated. Good agreements of the drag coefficient, lift coefficient and the Strouhal number are achieved with previous studies. It is found that both the Reynolds number and the Stokes number produce significant influences on the particle distribution. The small particles (St = 0.01) follow the motion of the fluid very well and can disperse into the core regions of the vortex structures. The particles at intermediate Stokes numbers (St = 0.1 and 1) concentrate on the boundaries of the vortices, and the large particles (St= 10) also assemble in the outer regions of the vortices under the influence of the vortex structures.