Flow Field Investigations of Two‐Stage Stirrer Configurations Combining Axially and Radially Conveying Turbines

In this study, the flow fields of two‐stage impellers, consisting of combinations of different impeller types on one shaft, are investigated using stereo particle image velocimetry. Based on the results of torque measurements, diameters for different impellers are determined in order to achieve matching power input of the individual turbines. When implemented adequately, both selected impellers are able to contribute their respective characteristics, resulting in flow fields that differ significantly from those induced by single‐stage impellers as well as two‐stage setups consisting of identical impellers.