The aim of this paper is to study the hydrodynamic behavior induced by a three different turbines: the FBT6 (six flat blades turbine), the RT6 (Rushton turbine), the PBT6 (pitched blades turbine). The turbulent flow generated in stirred tanks is numerically predicted by the resolution of the Navier-Stokes equation in conjunction with the RNG (Renormalization Group) of the k-epsilon turbulent model. These equations are solved by a control volume discretization method. The measurements were carried out for the one-stage and two-stage systems. The numerical results from the application of the CFD (computational fluid dynamics) code Fluent with the MRF (Multi Reference Frame) model are presented in the vertical and horizontal planes in the impeller stream region. The comparison between the numerical results and the experimental data showed a good agreement. (C) 2011 Elsevier Ltd. All rights reserved.