Conference on Turbulence and Interactions TI2006 May June Porquerolles France

Conference on Turbulence and Interactions TI2006, May 29 - June 2, 2006, Porquerolles, France LARGE EDDY SIMULATION OF AN AERATED RUSHTON STIRRED REACTOR D. Arlov†,?, J. Revstedt†, L. Fuchs† †Department of Energy Sciences, Division of Fluid Mechanics, Lund University, Lund, Sweden ?Email: ABSTRACT Simulations of aerated stirred reactor is performed using Large Eddy Simulation (LES). The gas phase is modelled using Lagrangian Particle Tracking (LPT). The reactor is stirred by a single impeller Rushton turbine, centred in the reactor. The air is introduced at the bottom wall through a circular sparger. The main focus is to investigate how the gas phase affects the liquid in the reactor. Effects of gas volume flow and stirrer speed are investigated. The results show that the time averaged liquid velocities in the radial and tangential directions as well as the pumping capacity decrease with increasing gas volume fraction. In the axial direction the gas redirects the radial jet upwards breaking the symmetry of the ring vortices. INTRODUCTION The dispersion of gases by agitated reactors is used extensively for example in biochemical pro- cesses. Issues concerning fluid flow inside the bioreactors are many such as explaining how the trailing vortices behind the impeller blades are affected by aeration and how the mixing in the reactor is influenced by the gas phase.

• gas redirects


• single phase


• tangential liquid velocity


• multi-grid method


• upwards creat- ing asymmetric


• tank


• time averaged