Rushton turbine, flow simulation

As in many other areas of CFD, advances in impeller treatment are occurring rapidly, both in developing new treatments and in making the established treatments more accurate and more efficient computationally. For example, Derksen and Van den Akker (1999) have applied an adaptive force field technique in a model of Rushton turbine flow. VanderHeyden et al. (private communication) at Los Alamos have developed a technique of switching a momentum source term at certain mesh node points on and off in a pattern that simulates the effect of a rotating impeller. These and other approaches promise increased fidelity with greater computational efficiency. 

Ranade, V.V., 1997. An efficient computational model for simulating flow in stirred vessels a case of Rushton turbine. Chemical Engineering Science, 52, 4473-4484. 

Fig. 13. Spatial distributions of bubble size in three vessels agitated by different impellers a classical Rushton turbine (DT), a hydrofoil impeller (A315) manufactured by Lightnin, and a Pitched Blade Impeller (PBT). The gas flow numbers in these simulations are in the range 0.01-0.02. These simulation results have been obtained by using GHOST Reproduced with permission from Bakker (1992).

Simulation of Flow Generated by a Disc (Rushton) Turbine... 

Derksen and van den Akker, H.E.A. (1999), Large eddy simulations on the flow driven by a Rushton turbine, AIChE /, 45, 209-221. 

Deshpande, V.R. and Ranade, V.V. (2001), Simulation of flow generated by dual Rushton turbines using computational snapshot approach, submitted for publication, Chem. Eng. Commun. 

Jenne, M. and Reuss, M. (1999), A critical assessment on the use of k-e turbulence model for simulation of the turbulent liquid flow induced by a Rushton turbine in baffled stirred tank reactor, Chem. Eng. ScL, 54, 3921-3941. 

Fig. 7.16. Simulating the effect of a Rushton turbine on the flow one practice is to impose empirical profiles for the physical quantities like Vr, vg, k and e on the vertical control surface bounding the impeller-swept region in a stirred vessel [10].

Lane et al [49] did compare the performance of simulations with the SM and the MRF approach in predicting flow fields within a standard stirred tank equipped with a Rushton turbine. Reasonable agreement with experimental data in terms of mean velocities is obtained with both methods. Nevertheless, the MRF method provides a saving in computational time of about an order of magnitude. 

Zakrzewska and Jaworski [101] performed single phase CFD simulations of turbulent jacket heat transfer in a Rushton turbine stirred vessel using the eight turbulence models mentioned above as implemented in FLUENT. In all simulations the boundary flow at the vessel wall was described by the... 

Derksen J, van den Akker HEA (1999) Large Eddy Simulations on the Flow Driven by a Rushton Turbine. AIChE J 45 (2) 209-221... 

Ranade, V.V. (1997). An Efficient Computational Model for Simulating Flow in Stirred Vessels a Case of Rushton Turbine, ChemESci. 53(24), pp. 4473 84. 

Khopkar, A.R., Rammohan, A.R., Ranade, V.V., and Dudukovic, M.P. (2005), Gas-Uquid flow generated by a rushton turbine in stirred vessel CARPT/CT measurements and CFD simulations, Chemical Engineering Science, 60(8-9) 2215-2229. 

A critical analysis of the many publications concerning the simulation of liquid flow in baffied stirred tank reactors equipped with a Rushton turbine reveals several discrepancies. The most important differences between the simulations concern the dimensionality of the simulations (three-dimensional or axisym-metric), turbulence modeling, the modeling approaches for the Rushton turbine as well as the accuracy of the numerical predictions, which depends on the grid size. 

Khopkar AR, Rammohan AR, Ranade W, Dudukovic MP Gas-liquid flow generated by a Rushton turbine in stirred vessel CARPT/CT measurements and CFD simulations, Chem Eng Sd 60 2215-2229, 2005. http //dx.doi.Org/10.1016/j.ces.2004.ll.044. 

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