Abstract
To deepen our knowledge of the flow in cyclones, the solids concentrations of different size particles in a scroll cyclone separator were
numerically simulated by using the Lagrange approach on the platform of commercial CFD software package, FLUENT 6.1. The numerical
calculations visualize that there exists a spiral dust strand near the cyclone wall and a dust ring beneath the cyclone top plate. There are two regions in
the radial solids concentration distribution, with which the solids concentration is low in the inner region (r/R(dimensionless radial position)≤0.75)
and increases greatly in the outer region (r/RN0.75). Large particles generally have higher concentration in the wall region and small particles have
higher concentration in inner vortex region. The axial distribution of the solids concentration in the inner vortex region (r/R≤0.3) shows that serious
fine particle re-entrainment exists within the height of 0.5 D (cyclone diameter) above the dust discharge port. We study the effect of solids particle on
the gas flow field by two-way couple. The concepts of back-mixing rate, first escaping rate and second escaping rate are proposed for quantifying the
local flow phenomena