This paper presents the computational fluid dynamics (CFD) analysis of the flow inside a cyclone with the division of gas and particle flow in a vortex finder. A doubled vortex finder which was used for the investigations divides gas cleaned in the cyclone into two parts. The gas elements exiting the cyclone through the external tube (i.e. bleed flow) were 20%, 40% and 57%, respectively. The particle size distribution of both streams has also been determined. The Reynolds-averaged Navier-Stokes equations with the Reynolds stress turbulence model (RSM) were used for the analysis. The Lagrangian method was employed to track the particle motion and calculate the cyclone and the efficiencies of division. The conducted division of exhaust gas practically does not change the gas flow and the efficiency of the cyclone. However, the particle size distribution of both gas streams is different. The difference in the particle size can be used for subsequent cleaning of bleed flow in a bag filter and for improving the efficiency of the modified system of the cyclone with an additional filter. Such a system would remove more dust than dividing the gas stream alone. (C) 2010 Elsevier B.V. All rights reserved.