Individual impeller flooding in aerated vessel stirred by multiple-Rushton impellers

The paper presents flooding detection in the dispersion of air into water in a stirred vessel equipped with a multiple-turbine impeller. All experiments were performed in a pilot-size mixing vessel using single, dual and triple Rushton turbine impellers. Deionized water and compressed air were used as a working fluid. The flooding recognition method based on resistivity probe response was applied, defining impeller flooding as the appearance of ragged cavities behind the blades of the individual impellers. Classifying the flooding regimes into a simple generalized flow map gave the sequence of impeller flooding: spreading from the lowest impeller flooding subsequently to the upper impellers. A comparison of our individual impeller-flooding data with the results found in the literature is shown for single impeller and partially for dual- and triple-turbine impeller, where due to the lack of published data only a comparison for the lowest turbine was possible.