LES-DPM simulation of turbulent gas-particle flow on opposed round jets

Abstract

A three-dimensional simulation was performed on the turbulent gas–solid flow in a cylindrical channel with opposed round jets. Large eddy simulation (LES) coupled with discrete phase model (DPM) was employed for carrier gas and laden particles respectively, to investigate the turbulent gas–solid behaviors. Simulations were focused on the effects of particle sizes (dp=5μm, 14μm and 40μm), Stokes numbers (St=0.125, 1 and 8), mass flux ratios (Zm=0.00128, 0.035 and 0.66) and initial gas velocities (U0=15m/s, 25m/s and 35m/s) on the vortex structure evolution, particle motion, time-averaged velocity profiles and turbulence intensity. It was found that the evolutions of vortex structure, including the destruction of large scale coherent structures to tiny vortices and the lateral spreading of vortices at the impingement zone, were augmented when using smaller particles and higher initial gas velocities. In addition, particles followed more closely and were easier to reach quasi-equilibrium state with the decrease of Stokes number (St<1), whereas more particles penetrated the impingement plane when increasing the Stokes number (St>1). And, with the increase of mass flux ratio, the momentum transfer was augmented as well as the turbulence intensity. Moreover, the position (rm) with maximum radial velocity was almost independent of the initial gas velocity on far-spaced opposed round jets.