Flow Patterns of Multiple Axial-Radial Impellers for Potential Use in Aerated Stirred Tanks

The hydrodynamics of a stirred tank equipped with multiple hybrid impellers was experimentally characterized. They were coaxially placed to agitate a viscous Newtonian fluid under gassed conditions. Experiments were performed by using the particle image velocimetry technique, and flow fields were reported in terms of the velocity magnitude, vertical currents, turbulent intensity, and strain rates. For comparison purposes, impellers providing radial flow (Rushton turbines) and axial flow (pitched blade turbines) were also tested. The results showed that hybrid impellers provided a uniform flow distribution throughout the tank at moderate strain rates, which make them an attractive alternative for fermentation processes with shear-sensitive cultures and viscous liquids.

Automated summary

The hydrodynamics of a stirred tank equipped with multiple hybrid impellers were experimentally characterized, and the results showed that the hybrid impellers provided a uniform flow distribution throughout the tank at moderate strain rates, making them an attractive alternative for fermentation processes with shear-sensitive cultures and viscous liquids.