Agitating liquids in unbaffled stirred tank leads to the formation of a vortex in the region of the impeller shaft when operating in the turbulent flow regime. A numerical model is presented here that captures such a vortex. The volume of fluid model, a multiphase flow model was employed in conjunction with a multiple reference frame model and the shear stress turbulence model. The dimensions of the tank considered here, were 0.585 m for the liquid depth and tank diameter with a 0.2925 m diameter impeller at a height of 0.2925 m. The impeller considered was an eight-bladed paddle type agitator that was rotating with an angular velocity of 7.54 rad s (72 rpm) giving a Reynolds number of 10 and Froude number of 0.043. Preliminary results of a second investigation into the effect of liquid phase properties on the vortex formed are also presented.
Bibliographical noteNOTICE: this is the author’s version of a work that was accepted for publication in Chemical engineering journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Glover, GMC & Fitzpatrick, JJ, 'Modelling vortex formation in an unbaffled stirred tank reactors' Chemical engineering journal, vol. 127, no. 1-3 (2007) DOI http://dx.doi.org/10.1016/j.cej.2006.09.019
- computation fluid dynamics
- free surface vortices
- stirred tanks
- volume of fluid.