Direct Numerical Simulation of Gas-Solid Flows in a Turbulent Channel Flow

Transport and deposition of aerosols in dilute and dense particle-laden flows is of considerable interest due to its importance in numerous industrial applications. In this study, the direct numerical simulations of gas-solid flows in a turbulent channel flow are analyzed. Particular attention was given to the deposition of particles on the walls. The interaction of turbulent eddies with small particle is discussed. The effect of inter-particle collisions and two-way coupling on the particle deposition velocity in turbulent duct flows is investigated. The time history of the instantaneous turbulent velocity vector was generated by the two-way coupled direct numerical simulation (DNS) of the Navier-Stokes equation via a pseudospectral method. The particle equation of motion takes the Stokes drag, the Saffman lift, and the gravitational forces into account. The effect of particles on the flow is included in the analysis via a feedback force on the grid points. Several simulations for different particle relaxation times, density ratios and mass loadings of the particles were performed, and the effect of inter particle collisions and two-way coupling on the turbulent eddy structure and particle deposition velocity were discussed. It was found that the inter-particle collisions increase the particle deposition velocity.

Keywords:

DNS , Turbulent Flows , Gas-Solid Flows , Dense flows , Particle Deposition