Revisiting the Performance of a Coaxial Mixer

Abstract

The performance of a coaxial mixer combining an anchor and a Rushton turbine was investigated for different diameter ratios and rotating modes in the laminar and transition flow regimes. Based on mixing efficiency criteria, this study confirmed that the co-rotating mode is consistently yielding the best results in the laminar and early transition regimes. The best performance was obtained for a turbine to tank diameter ratio of 1/3. In the upper transition and turbulent regimes, the best performance was obtained with the anchor at rest acting like two opposed baffles. With such a configuration, the optimum diameter ratio was found to be 1/2. New definitions of Reynolds number and power number were also introduced based on new characteristic diameter and speed. These correlations shown to be applicable for radial and axial impellers and are significantly better than the ones proposed in the literature.

Computational fluid dynamic studies of mixers for highly viscous shear thinning fluids and PIV validation

“…In contrast, anchor impellers have larger constants of around 23 (Pakzad et al, 2013a). Different methodologies have been proposed to obtain power curves for coaxial mixers (Thibault and Tanguy, 2002, Foucault et al, 2004, Farhat et al, 2008, Pakzad et al, 2013a, but direct comparison of power consumption between single and coaxial impellers has not been reported in the literature.…”

Power consumption and flow field characteristics of a coaxial mixer with a double inner impeller

“…The earliest work was reported by Schneider and Todtenhaupt of EKATO Company [7]. Afterwards, Canadian Tanguy's group did systematic researches on the performance of coaxial mixers, which were composed of an anchor agitator and Rushton turbine impeller or Sevin propeller or Deflo-Sevin impeller [8][9][10][11]. Their studies were mainly focused on the influences of rotation modes and speed ratios on power consumption and mixing performance.…”

Mixing of Complex Fluids in a Cylindrical Tank by a Modified Anchor Impeller

“…Foucault et al . and Farhat et al . studied co‐axial impeller systems composed of an anchor impeller combined with different turbines (Mixel TT impeller, Rushton and sawtooth).…”