Modelling SGS-Turbulent Transport of Fine Particles with Application to Cyclone Separator Performance

Unsteady, technically relevant particle-laden flows are nowadays efficiently simulated with an LES-Euler/Lagrange approach. The present contribution is related to fine particle separation in a gas cyclone which involves an unsteady central vortex being responsible for particle separation. Particle motion is largely controlled by near-wall transport processes including wall collisions as well as near-wall turbulence. Naturally, in a LES this region is not very well resolved so that a remarkable contribution to the local turbulence is included in the modelled sub-grid-scale (SGS) turbulence. In this paper the importance of SGS turbulence on particle transport is analysed. It is shown that neglecting the SGS contribution to the particle transport yields a wrong prediction of the particle size-dependent separation of a cyclone.