Computational Flow Modelling of Dual Rushton Impeller Stirred Vessels

Flow in baffled stirred vessels involve interactions between flow around rotating impeller blades and stationary baffles. When more than one impeller is used, which is quite common in practice, the flow complexity is greatly increased, especially when there is an interaction between the multiple impellers. The extent of interaction depends on relative distances between the impellers and clearance from the vessel bottom. A computational tool which can "a priori" predict the interaction between the multiple impellers, can hence be used in the design of stirred tank reactors. In this paper, we evaluate the ability of predicting such interaction between the flow generated by two Rushton impellers using a modified computational snapshot approach. A case of fully baffled vessel equipped with two standard Rushton turbines (DT) is considered. The geometry of the vessel and other operating parameters were same as those reported in [4]. Flow generated for three different impeller configurations, corresponding to three stable flow patterns observed by them has been investigated. A standard k " model was used for turbulence. The predicted flow characteristics were compared with the published experimental data, including overall impeller characteristics such as pumping number and power number. The satisfactory comparison indicate the potential usefulness of this approach as a computational tool for designing stirred reactors.