Laminar Flow Characterization in a Stirred Tank with a Gate Impeller in Case of a Non-Newtonian Fluid

A large number of chemical operations, biochemical or petrochemical industry is very depending on the rheological fluids nature. In this work, we study the case of highly viscous fluids in a classical system of agitation: a cylindrical tank with plate bottom without obstacles agitated by a gate impeller agitator. We are interested to the laminar, incompressible and flow. We devote to a numerical approach carried out using an industrial code CFD Fluent 6.3.26 based on the finite volumes method discretization of Navier - Stokes equations formulated in variables (U.V.P). The threshold of flow related to the viscoplastic behaviour is modelled by a theoretical law of Bingham. The results obtained are used to compare between the five configurations suggested in terme of power consumption. We study the influence of inertia by the variation of Reynolds number and generalized Reynolds number and the plasticity influence by the variation of Bingham number on the flow. The fields speed are analyzed, we note the existence of a threshold of flow characterized by the number of Hedstrom can lead to a quasi-immobilization of zones inside the system of agitation for all configurations suggested. (C) 2013 The Authors. Published by Elsevier Ltd.