Large-eddy simulations (LES) of a'vertical turbulent channel flow laden with a large number of solid point particles are discussed. This flow is relevant for a better understanding of co·current turbulent gas-particle flows. as encountered in riser reactors. The particle volume fraction is chosen to be high, it equals about 1.3%. This necessitates the use of a four-way coupling model for the discrete particle dynamics. The Euler-Lagrangian method is adopted, which means that the fluid dynamics is governed by the Navier-Stokes equations and that the motion of individual particles is tracked by solving their equation of motion, taking both theparticle-fluid and particle-particle interactions into account. LES results are compared to single·phase channel flow to investigate the effect of the particles on turbulent statistics. Due 10 particle-fluid interactions the mean fluid profile is flattened and the boundary layer is thinner. Compared to single-phase turbulent flow, the streamwise turbulence intensity of the gas phase is increased, while the normal and spanwise turbulence intensities are reduced, as is also observed in experimental data. The four-way coupled simulations are also compared with twoway coupled simulations. in which the inelastic collisions between particles are neglected. The latter comparison demonstrates that the collisions have a large influence on the main statistio;,s of both phases. expressed for example by the stronger coherent particle structures observed in four·way coupling.
|Name||Lecture Notes in Applied and Computational Mechanics|
|Conference||International Colloquium on Multiscale Methods in Computational Mechanics, MMCM 2009|
|Period||11/03/09 → 13/03/09|
- Large eddy simulation
- Channel flow
- Particle-laden turbulence
- Four-way coupling