Design Considerations in Laminar Fluid Mixing with Unconventional Geometries

Abstract

Laminar mixing in stirred vessels is often inefficient due to the presence of flow
structures generated during the process. Very long mixing times are then required for achieving a specific homogeneity level into the tank. Although the easiest way of removing such structures consist of increasing the impeller rotational speed, in many cases the turbulent regime cannot be achieved due to excessive media heating by viscous dissipation, torque limitations on the kinematic chain, and the costly power consumption. To alleviate these obstacles, alternate configurations specifically designed for operation in the laminar regime have been introduced. This paper deals
with a review of these non-typical alternate configurations based mainly on off-centered impellers, multi-shaft equipment and planetary mixers. It will be shown that the performance of these systems paves the way to a new technological paradigm in laminar mixing.