Modelling of Turbulence in Stirred Vessels Using Large Eddy Simulation

The application of large eddy simulation (LES) to the prediction of large-scale chaotic structures in stirred tanks is investigated. Typical stirrer configurations representing different flow regimes are assessed: a single radial pumping impeller, single axial pumping impellers, multiple hydrofoil impellers, and a retreat curve impeller. The dynamic turbulent flow field in each configuration is calculated using LES. The impeller motion is explicitly modelled using the sliding mesh model. It is concluded that the flow fields in stirred vessels are very rich in structure and that a wide variety of flow regimes exist. The predicted flow patterns compare well with digital particle image velocimetry data reported in the literature, and exhibit the long time-scale instabilities seen in experiments reported in the literature.

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