Hydrodynamic Study in a Cone Bottom Stirred Tank Using Computational Fluid Dynamics

Cardona, L. F.; Arismendy, J. E.; Quintana, G. C.; Alzate, H. H.

doi:10.47176/jafm.16.10.1724

Hydrodynamic Study in a Cone Bottom Stirred Tank Using Computational Fluid Dynamics

Document Type : Regular Article

Authors

¹ Pulp and Paper Research Group, Faculty of Chemical Engineering, Universidad Pontificia Bolivariana, Medellín 56006, Colombia

² Department of Basic Sciences, Universidad Católica Luis Amigó, Medellín 050034, Colombia

10.47176/jafm.16.10.1724

Abstract

Stirred tanks are often used in industrial applications to store and process liquids and solids. However, these systems have become an increasing challenge to improve and optimize these processes. Computational Fluids Dynamics (CFD) simulation predicts complex phenomena as hydrodynamics system performance. An optimal solution is found using an effective mesh scheme and selecting appropriate boundary conditions. This work aims to validate and describe the distribution velocities inside the tank using a rigorous turbulence model. Stirred tank with a diameter of 27 cm and an oval cone tip using a Rushton impeller (radial impeller) and a 4-blade impeller inclined at 45° (axial impeller) are performed. For both cases, hydrodynamics in the bottom tank is analyzed. In addition, the power and the pumping numbers for each impeller are studied. The overall results show that at the tip of the oval cone, the asymmetry in the mesh is improved, and the divergence in the solution is avoided. Also, the cone designer increased the turbulent kinetic energy, which can enhance the mixture process. A decrease in power impeller is shown when the axial type is applied at low Reynolds numbers; however, when the cone is introduced inside the tank and a radial impeller type is used, the impeller power values are increased. The overall results of CFD simulation are compared to experimental data and provide similar values with an absolute deviation below 4.46 %.

Keywords

Main Subjects

Turbulence simulation

References

Ansys Fluent 12. (2009). Fluid Simulation Software. (version 12) [software]. https://www.ansys.com/products/fluids/ansys-fluent##

Baba, A. F., Samiran, N. A., Abd Rashid, R., Ishak, I. A., Salleh, Z. M., Madon, R. H., & Hamid, M. S. S. (2022). Effect of impeller’s blade number on the performance of mixing flow in stirred tank using CFD simulation method. CFD Letters, 14(5), 33-42. https://doi.org/10.37934/cfdl.14.5.3342##

Bakker, A. (2006). Modeling Flow Fields in Stirred Tanks: Reacting Flows - Lecture 7(FLUENT). https://www.bakker.org/##

Chapple, D., Kresta, S. M., Wall, A., & Afacan, A. (2002). The effect of impeller and tank geometry on power number for a pitched blade turbine. Chemical Engineering Research and Design, 80(4), 364-372. https://doi.org/10.1205/026387602317446407##

Chudacek, M. W. (1985). Solids suspension behaviour in profiled bottom and flat bottom mixing tanks. Chemical Engineering Science, 40(3), 385-392. https://doi.org/10.1016/0009-2509(85)85100-9##

Coroneo, M., Montante, G., Paglianti, A., & Magelli, F. (2011). CFD prediction of fluid flow and mixing in stirred tanks: Numerical issues about the RANS simulations. Computers & Chemical Engineering, 35(10), 1959-1968. https://doi.org/10.1016/j.compchemeng.2010.12.007##

Couturier, M., Trofimencoff, T., Buil, J. U., & Conroy, J. (2009). Solids removal at a recirculating salmon-smolt farm. Aquacultural Engineering, 41(2), 71-77. https://doi.org/10.1016/j.aquaeng.2009.05.001##

Delgadillo, J. A., & Rajamani, R. K. (2005). A comparative study of three turbulence-closure models for the hydrocyclone problem. International Journal of Mineral Processing, 77(4), 217-230. https://doi.org/10.1016/j.minpro.2005.06.007##

Desobgo, S. C. Z. (2018). Modernization of fermenters for large-scale production in the food and beverage industry. Innovations in Technologies for Fermented Food and Beverage Industries, 189-220. https://doi.org/10.1007/978-3-319-74820-7_11##

Devi, T. T., & Kumar, B. (2011). Analyzing flow hydrodynamics in stirred tank with CD-6 and Rushton impeller. International Review of Chemical Engineering, 3(4), 440-448.##

Devi, T. T., & Kumar, B. (2012). CFD simulation of flow patterns in unbaffled stirred tank with CD-6 impeller. Chemical Industry and Chemical Engineering Quarterly, 18(4-1), 535-546. https://doi.org/10.2298/CICEQ111130029D##

Dong, J., Hu, B., Pacek, A. W., Yang, X., & Miles, N. J. (2016). The effect of bottom shape and baffle length on the flow field in stirred tanks in turbulent and transitional flow. International Journal of Mechanical and Mechatronics Engineering, 10(9), 1651-1660. https://doi.org/10.5281/zenodo.1126537##

Doran, P. M. (1995). Bioprocess Engineering Principles. Academic Press.##

el Mezaini, N. (2006). Effects of soil-structure interaction on the analysis of cylindrical tanks. Practice periodical on Structural Design and Construction, 11(1), 50-57. https://doi.org/10.1061/(ASCE)1084-0680(2006)11:1(50)##

Guha, D., Ramachandran, P. A., Dudukovic, M. P., & Derksen, J. J. (2008). Evaluation of large Eddy simulation and Euler‐Euler CFD models for solids flow dynamics in a stirred tank reactor. AIChE Journal, 54(3), 766-778. https://doi.org/10.1002/aic.11417. http://www.bakker.org/dartmouth06/engs199/09-blend.pdf##

Jakobsen, H. A. (2008). Chemical reactor modeling. Multiphase Reactive Flows. Springer International Publishing.##

Khapre, A., & Munshi, B. (2014). Numerical comparison of Rushton turbine and CD-6 impeller in non-Newtonian fluid stirred tank. International Journal of Chemical and Molecular Engineering, 8(11), 1260-1267. https://doi.org/10.5281/zenodo.1097247##

Landucci, G., Antonioni, G., Tugnoli, A., & Cozzani, V. (2012). Release of hazardous substances in flood events: Damage model for atmospheric storage tanks. Reliability Engineering & System Safety, 106, 200-216. https://doi.org/10.1016/j.ress.2012.05.010##

Lane, G., & Koh, P. T. L. (1997, july). CFD simulation of a Rushton turbine in a baffled tank. Proceedings International Conference on Computational Fluid Dynamics in Mineral and Metal Processing and Power Generation, CSIRO, Melbourne, Australia. https://www.cfd.com.au/cfd_conf97/papers/lan035.pdf##

Liangchao, L., Ning, C., Kefeng, X., & Beiping, X. (2019). CFD study on the flow field and power characteristics in a rushton turbine stirred tank in laminar regime. International Journal of Chemical Reactor Engineering, 17(11), 1-17. https://doi.org/10.1515/ijcre-2018-0215##

Martínez-Nelis, F. M. (2010). Estudio numérico de la fluidodinámica de un estanque de agitación utilizando método de mallas deslizantes [Bachelor thesis, Universidad de Chile]. https://repositorio.uchile.cl/handle/2250/103931##

McCabe, W. L., Smith, J. C., & Harriott, P. (2007). Unit Operations of Chemical Engineering. McGraw-Hill.##

Mendoza-Escamilla, V. X., Alonzo-García, A., Mollinedo, H. R., González-Neria, I., Yáñez-Varela, J. A., & Martinez-Delgadillo, S. A. (2018). Assessment of k–ε models using tetrahedral grids to describe the turbulent flow field of a PBT impeller and validation through the PIV technique. Chinese Journal of Chemical Engineering, 26(5), 942-956. https://doi.org/10.1016/j.cjche.2018.02.012##

Micale, G., Montante, G., Grisafi, F., Brucato, A., & Godfrey, J. (2000). CFD simulation of particle distribution in stirred vessels. Chemical Engineering Research and Design, 78(3), 435-444. https://doi.org/10.1205/026387600527338##

Montante, G., Lee, K. C., Brucato, A., & Yianneskis, M. (2001). Numerical simulations of the dependency of flow pattern on impeller clearance in stirred vessels. Chemical Engineering Science, 56(12), 3751-3770. https://doi.org/10.1016/S0009-2509(01)00089-6##

Mustafa, S., Taha, M. M., Zatout, A. A., Sedahmed, G. H., & El-Gayar, D. A. (2021). Mass transfer at the outer surface of a spiral tube heat exchanger in a stirred tank reactor and possible applications. Chemical Engineering Research and Design, 165, 426-434. https://doi.org/10.1016/j.cherd.2020.11.023##

Naeeni, S. K., & Pakzad, L. (2019). Droplet size distribution and mixing hydrodynamics in a liquid–liquid stirred tank by CFD modeling. International Journal of Multiphase Flow, 120, 103100. https://doi.org/10.1016/j.ijmultiphaseflow.2019.103100##

Nagy, P., & Juhasz, J. (2016). Review of present knowledge on machine milking and intensive milk production in dromedary camels and future challenges. Tropical Animal Health and Production, 48(5), 915-926. https://doi.org/10.1007/s11250-016-1036-3##

Nili-Ahmadabadi, M., Durali, M., & Hajilouy, A. (2014). A novel aerodynamic design method for centrifugal compressor impeller. Journal of Applied Fluid Mechanics, 7(2), 329-344. https://doi.org/10.36884/JAFM.7.02.20279##

Paul, E. L., Atiemo-Obeng, V. A., & Kresta, S. M. (2004). Handbook of Industrial Mixing: Science and Practice. John Wiley & Sons.##

Prabhu, M., Sreenath, K., Ajith Kumar, R., Jayakumar, J. S., & Joshy, P. J. (2021). Rankine vortex suppression in tanks with conical base: a numerical investigation. Journal of Spacecraft and Rockets, 58(2), 326-333. https://doi.org/10.2514/1.A34794##

Pukkella, A. K., Vysyaraju, R., Tammishetti, V., Rai, B., & Subramanian, S. (2019). Improved mixing of solid suspensions in stirred tanks with interface baffles: CFD simulation and experimental validation. Chemical Engineering Journal, 358, 621-633. https://doi.org/10.1016/j.cej.2018.10.020##

Qi, N., Zhang, H., Zhang, K., Xu, G., & Yang, Y. (2013). CFD simulation of particle suspension in a stirred tank. Particuology, 11(3), 317-326. https://doi.org/10.1016/j.partic.2012.03.003##

Singh, H., Fletcher, D. F., & Nijdam, J. J. (2011). An assessment of different turbulence models for predicting flow in a baffled tank stirred with a Rushton turbine. Chemical Engineering Science, 66(23), 5976-5988. https://doi.org/10.1016/j.ces.2011.08.018##

Sivakumar, V., Visagavel, K., & Selvakumar, A. (2017). Analysis of Ventilation Rate in Cross Ventilated Rooms by Varying Aperture Shape of Windows using CFD. Journal of Applied Fluid Mechanics, 10, 61-68. https://doi.org/10.36884/JAFM.10.SI.28271##

Su, T., Yang, F., Li, M., & Wu, K. (2018). Characterization on the hydrodynamics of a covering-plate Rushton impeller. Chinese Journal of Chemical Engineering, 26(6), 1392-1400. https://doi.org/10.1016/j.cjche.2017.11.015##

Tahani, M., & Moradi, M. (2016). Aerodynamic investigation of a wind turbine using CFD and modified BEM methods. Journal of Applied Fluid Mechanics, 9(1), 107-111. https://doi.org/10.36884/jafm.9.SI1.25820##

Todaro, C. M., & Vogel, H. C. (2014). Fermentation and biochemical engineering handbook. William Andrew.##

Van den Akker, H. E. (2006). The details of turbulent mixing process and their simulation. Advances in Chemical Engineering, 31, 151-229. https://doi.org/10.1016/S0065-2377(06)31003-4##

Venneker, B. C., Derksen, J. J., & Van den Akker, H. E. (2010). Turbulent flow of shear-thinning liquids in stirred tanks—The effects of Reynolds number and flow index. Chemical Engineering Research and Design, 88(7), 827-843. https://doi.org/10.1016/j.cherd.2010.01.002##

Versteeg, H. K., & Malalasekera, W. (2007). An introduction to computational fluid dynamics: the finite volume method. Prentice Hall.##

Wu, H., & Patterson, G. K. (1989). Laser-Doppler measurements of turbulent-flow parameters in a stirred mixer. Chemical Engineering Science, 44(10), 2207-2221. https://doi.org/10.1016/0009-2509(89)85155-3##

Xia, B., & Sun, D. W. (2002). Applications of computational fluid dynamics (CFD) in the food industry: a review. Computers and Electronics in Agriculture, 34(1-3), 5-24. https://doi.org/10.1016/S0168-1699(01)00177-6##

Youcef, K., Bouzit, M., Hadjeb, A., Arab, I. M., & Beloudane, M. (2016). CFD study of the effect of baffles on the energy consumption and the flow structure in a vessel stirred by a Rushton turbine. Mechanics, 22(3), 190-197. https://doi.org/10.5755/j01.mech.22.3.12663##

Zadghaffari, R., Moghaddas, J. S., & Revstedt, J. (2009). A mixing study in a double-Rushton stirred tank. Computers & Chemical Engineering, 33(7), 1240-1246. https://doi.org/10.1016/j.compchemeng.2009.01.017##