Which impeller should be chosen for efficient solid-liquid mixing in the
laminar regime?
Abstract
The vast majority of solid-liquid mixing studies have focused on high
Reynolds number applications with configurations and impeller geometries
adapted to this type of regime. However, the mixing of particles in a
viscous fluid is an essential element of many contemporary industries.
We used the CFD-DEM model previously developed in our group to
investigate solid-liquid mixing with close-clearance impellers in the
laminar regime of operation. We compared different geometries that is,
the double helical ribbon, anchor, Paravisc$^{TM}$, and
Maxblend$^{TM}$ impellers. We investigated the impact of fluid
viscosity and compared the results with those obtained with the pitched
blade turbine, a more commonly used impeller, based on power consumption
for equivalent mixing states. This study highlights that the higher the
viscosity of the fluid, the more interesting it is to use
close-clearance impellers for their ability to generate a strong shear
stress and a strong bulk flow in the entire vessel.