AN EFFICIENT COMPUTATIONAL MODEL FOR SIMULATING FLOW IN STIRRED VESSELS - A CASE OF RUSHTON TURBINE

Computational tools are being increasingly used to analyse flow and mi xing in baffled stirred vessels. In a baffled stirred vessel, flow aro und the rotating impeller blades interacts with stationary baffles and generates a complex, three-dimensional, recirculating turbulent flow. We have developed an efficient computational model, in which a quasi- steady flow is computed for any momentary impeller position. This mode l adequately captures most of the significant details of the flow both within and outside the impeller without requiring any empirical input /adjustable parameter. The method was applied to the flow generated by a standard Rushton turbine, for which detailed experimental data are available. A case of fully baffled vessel with standard Rushton turbin e (DT) was simulated using FLUENT code. The impeller rotation was mode lled in terms of appropriate source terms at the blade surfaces. The l aminar and turbulent flow generated by DT were simulated using this mo del. The model predictions were validated by comparisons with the publ ished experimental data. Overall impeller performance characteristics like pumping number and power number were also compared with the exper imental data for both, laminar and turbulent flow regimes. The approac h presented here can be used as a general purpose, mixer design tool. (C) 1997 Elsevier Science Ltd.