Turbulent flow and mixing enhancement
Stirred vessels are widely used throughout the process industry; mixing in stirred chemical reactors affects around 25% of all process industry operations. Insufficient or excessive mixing may result in wastage of processing time, raw material and/or formation of by-product. In this context, our work has focused on improving the mixing performance of stirred vessels with the aid of accurate numerical simulations (that go beyond the standard RANS approach). Initial work was based on Large Eddy Simulation (LES), and more recent work on DNS. Our latest simulations show that impellers with irregular blades have both smaller energy consumption and also lead to shorter mixing times in comparison to impellers with regular blades. The simulations provide a detailed picture of the differences in the flow and scalar fields that can explain the improved performance characteristics. Part of this work was carried out in collaboration with Prof. J.C. Vassilicos.
- Yeoh, SL, Papadakis, G, Lee, KC and Yianneskis, M (2004) Large Eddy Simulation of turbulent flow in a Rushton impeller stirred reactor with sliding-deforming mesh methodology. Chemical Engineering & Technology, vol. 27 (3), pp. 257-263.
- Yeoh, S.L., Papadakis, G. and Yianneskis, M. (2004) Numerical simulation of Turbulent flow characteristics in a stirred vessel using the LES and RANS approaches with the sliding/deforming mesh methodology. Transactions of the Institution of Chemical Engineers (IChemE), Chemical Engineering Research and Design, Part A, vol. 82(A7), pp 834-848.
- Micheletti, M., Baldi, S., Yeoh, S.L., Ducci, A., Papadakis, G., Lee, K.C. and Yianneskis, M. (2004) On spatial and temporal variations and estimates of energy dissipation in stirred reactors. Transactions of IChemE, Chemical Engineering Research and Design, Part A, vol. 82(A9), pp 1188-1198.
- Yeoh, S. L., Papadakis, G. and Yianneskis, M. (2005) Determination of Mixing Time and Degree of Homogeneity in Stirred Vessels with LES. Chemical Engineering Science, vol. 60, pp 2293-2302
- Rice, M., Hall, J., Papadakis, G. and Yianneskis, M. (2006) Investigation of laminar flow in a stirred vessel at low Reynolds numbers. Chemical Engineering Science, Vol. 61, pp. 2762-2770, 2006.
- Basbug, S., Papadakis, G. and Vassilicos, J.C. (2017) DNS Investigation of the Dynamical Behaviour of Trailing Vortices in Stirred Vessels at Transitional Reynolds Numbers, Physics of Fluids, vol 29, 064101.
- Basbug, S., Papadakis, G. and Vassilicos, J.C (2018) Reduced power consumption in stirred vessels by means of fractal impellers, AIChE Journal, 64:1485-1499 [paper selected as Editor’s choice in Transport Phenomena and Fluid Mechanics]
- Basbug S, Papadakis G, Vassilicos JC. (2018) Reduced mixing time in stirred vessels by means of irregular impellers, Physical Review Fluids, 3, 084502.
- Basbug, S. (2017) Flow field and mixing in stirred vessels with regular and fractal impellers, PhD thesis, Dept. of Aeronautics, Imperial College London.
- S.L. Yeoh (2004) Large Eddy Simulation of turbulent flow and mixing in a stirred vessel, PhD thesis, Dept. of Mech. Eng., King’s College London.