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International Journal of Chemical Engineering
Volume 2012 (2012), Article ID 450491, 11 pages
http://dx.doi.org/10.1155/2012/450491
Research Article

Mixing Study in an Unbaffled Stirred Precipitator Using LES Modelling

1Nuclear Energy Division, Radiochemistry and Processes Department, French Alternative Energies and Atomic Energy Commission, 30207 Bagnols sur Ceze, France
2Nuclear Energy Division, Reactor Studies Department, French Alternative Energies and Atomic Energy Commission, 34054 Grenoble, France
3Reactions and Process Engineering Laboratory, CNRS, 54001 Nancy, France

Received 9 December 2011; Revised 8 March 2012; Accepted 14 March 2012

Academic Editor: Nandkishor Nere

Copyright © 2012 Murielle Bertrand et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper describes the CFD modelling of a reactor operating in the nuclear industry using LES approach. The reactor consists of an unbaffled stirred tank reactor in which plutonium precipitation reactions are carried out. The flow generated in such a precipitator is complex and there is very little information available in the literature about unbaffled reactors stirred with magnetic rod. That is why a hydrodynamic modelling has been developed using computational fluid dynamics (CFD) in order to get accurate description of mixing phenomena inside the precipitator and therefore to be able to predict the solid particle properties. Due to the strong turbulence anisotropy, the turbulence transport simulation is achieved by a large eddy simulation (LES) approach which gives unsteady solutions. The numerical simulations are performed in 3D using the Trio_U code developed at the Commissariat à l'Énergie Atomique. The predictive performances of the modelling are analysed through a mixing phenomena study. Both experimental and numerical studies are performed. This work shows how hydrodynamics inside the reactor can have a noticeable effect on the precipitate properties and how LES modelling is a very effective tool for the process control.