Numerical simulation of particle-laden turbulent channel flow

This paper presents results for the behavior of particle-laden gases in a s mall Reynolds number vertical channel down flow. Results will be presented for the effects of particle feedback on the gas-phase turbulence and for th e concentration profile of the particles. The effects of density ratio, mas s loading, and particle inertia will be discussed. The results were obtaine d from a numerical simulation that included the effects of particle feedbac k on the gas phase and particle-particle collisions. The resolution of the simulation was comparable to the smallest scales in the particle-free flow, but the grid spacings were larger than the particle size. Particle mass lo adings up to 2 and both elastic and inelastic collisions were considered. P article feedback causes the turbulent intensities to become more anisotropi c as the particle loading is increased. For small mass loadings, the partic les cause an increase in the gas flow rate. It will be shown that the parti cles tend to increase the characteristic length scales of the fluctuations in the streamwise component of velocity and that this reduces the transfer of turbulent energy between the streamwise component of velocity and the co mponents transverse to the flow. Particle-particle collisions greatly reduc e the tendency of particles to accumulate at the wall for the range of mass loadings considered. This was true even when the collisions were inelastic . (C) 2001 American Institute of Physics.