Large eddy simulation of a gas-particle two dimensional backward-facing step flow

The two-dimensional gas-particle two phase turbulent two-dimensional backward-facing step flow was studied by numerical method. Gas field was simulated by large eddy simulation (LES) and solid particle motion was traced by particle track model. The standard Smagorinsky sub-grid model was used to model motions of small-scale structures. The simulation attained the large eddy coherent structures evolving spatially and temporally. The time average mean velocity agreed well with the experimental data. Then, the particle motions with various particle Stokes numbers and different initial two-phase velocity slip conditions were discussed deeply. The research shows that the initial two phase velocity slip plays an important role in enforcing particles dispersion when the particle Stokes numbers are larger. The particle phase temporal statistic velocity fields of glass bead in diameter of 150 μm were also attained, which agreed well with the experimental results. The present research paves a way for the further study of turbulence modification of two-phase flow.