In this study, the dense flow characteristics in a Lapple cyclone were investigated using numerical simulations. At a high solid volume fraction, four-way coupling must be applied to account for solid volume fraction in Navier-Stokes equations and particle-particle collisions, which are not considered in one- and two-way couplings approaches. A four-way coupling method, the dense discrete phase model (DDPM), which accounts for the solid volume fraction, was used in this study. The kinetic theory of granular flow (KTGF) in the DDPM was utilized to compute particle-particle interactions. The calculated results obtained using DDPM-KTGF were validated using experimental results reported previously. These results were compared with numerical data obtained from the discrete element model (DEM), which is another four-way coupling method. DDPM-KTGF could be successfully applied to situations involving high solid volume fractions with a significantly lower computational time than that required for DEM. (C) 2019 Elsevier B.V. All rights reserved.