Philippe A. Tanguy1, Mourad Heniche2, Arash Iranshahi2, and Katsuhide Takenaka3. (1) Chemical Engineering Department, École Polytechnique de Montréal, P.O. Box 6079, Station Centre-Ville, Montréal, QC H3C 3A7, Canada, (2) Dept. of Chemical Engineering, Unité de Recherche sur les Procédés d'Écoulements Industriels (URPEI), École Polytechnique de Montréal, P.O. Box 6079, Station Centre-Ville, Montréal, QC H3C 3A7, Canada, (3) R&D Dept., SHI Mechanical & Equipment Inc., 1501 Imazaike, Toyo City, Ehime, Japan
Sumitomo's Maxblend impeller has been shown to operate very efficiently in the upper laminar and transition regime. In the deep laminar regime, however, secondary flows are induced behind the bottom paddle that hampers adequate up-pumping in this region. As a result, flow segregations are generated, which are detrimental to mixing efficiency. In order to address this issue, 3D finite element CFD simulations have been used to optimize the shape of the bottom paddle of the Maxblend impeller. In this presentation, it will be shown that appropriate design modifications minimize the occurrence of segregations and enhance significantly the bottom-to-top pumping in the lower part of the vessel at very low Reynolds number, extending the range of applicability of the Maxblend impeller in the creeping flow regime.