Asymmetric Blade Impeller

The Colorful Fluid Mixing Gallery

Chemineer, Inc. recently released a new patented gas dispersion impeller (BT-6) with asymmetric concave blades. A copy of the patent is available in MS-Word 97 format (395kB) or Acrobat PDF Format (1135kB). This page shows some results of CFD simulations of the flow in a vessel equipped with such an impeller. All simulations were done using Fluent V5 from Fluent, Inc.

This work was also presented at IChemE's "John Smith's Day" at the University of Birmingham in January, 2000, under the title "A New Gas Dispersion Impeller with Vertically Asymmetric Blades" (PDF file; 1.2Mb).

Here we see the velocity magnitudes in a horizontal plane through the impeller. The highest velocities are found near the tip of the impeller blades. The impeller creates a radial jet. It is rotating clockwise, with the concave ("open") face forward.

The impeller, shaft, baffles, bottom, and liquid surface are colored by liquid velocity magnitude. Red and blue denote high and low velocities respectively. The highest velocities are found on the impeller blades. The simulations predicted a power number of 2.2, which is within 5% of the measured power number.

The simulations were performed using a multiple reference frame (MRF) model. A fully unstructured tetrahedral mesh was used, with approximately 400k nodes. The mesh was relatively fine near the impeller blades and coarser far away from the impeller.

This image shows the grid on the tank walls.

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Last Updated December 16, 1998 by André Bakker
© André Bakker 1998