In this study, first, the effect of different state-of-the-art dispersion and particle-wall collision models on the efficiency and erosion prediction are investigated. Second, the influence of particle size on the erosion pattern is explored. These assessments require reliable sub-model inputs, e.g. velocity statistics, which are provided through a large eddy simulation. The results reveal that a dispersion model for cyclone applications should account for the effect of anisotropic normal and shear Reynolds stresses and the "drift correction". Furthermore, the erosion inside a cyclone can have four critical zones based on the particle size. It is also proven that the accurate prediction of erosion pattern necessitates the inclusion of the Saffman and Magnus lift forces on particles and realistic variable restitution coefficients in the particle-wall collision model. Finally, wall roughness increases the erosion rate of large particles through the combined impact of the "shadow effect" and energetic inner vortex on particles. (C) 2019 Elsevier B.V. All rights reserved.