Design of a Gas–Liquid Unbaffled Stirred Tank with a Concave Blade Impeller
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Experimental investigation of unbaffled multiphase (gas–liquid) stirred tanks is conducted with the use of a concave blade impeller to analyze mass transfer, gassed power, and gas holdup. The experiments are carried out with various impeller diameter to tank diameter ratios and impeller clearances. The design criterion for the mass transfer rate is proposed, and its prediction capability is found to be satisfactory. The results show that the gassed power is dependent on the impeller diameter to tank diameter ratio and impeller clearance. The design criteria for gassed power to ungassed power ratio and gas holdup are also introduced. Multiphase modeling is done by employing the computational fluid dynamics (CFD) techniques to observe the characteristic flow pattern transition and to carry out a qualitative analysis of the mass transfer rate.
Keywordsconcave blade impeller gas holdup impeller clearance mass transfer power number stirred tank
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- 3.A. Karimi, F. Golbabaei, M. Neghab, M. R. Mehrnia, K. Mohammad, M. R. Pourmand, and A. Nikpey, Investigation of oxygen transfer in a two-phase partition stirred tank bioreactor in the presence of silicone oil, Chem. Biochem. Eng. Q., 25, 209–219 (2011).Google Scholar
- 9.M. Cooke, J. C. Middleton, and J. R. Bush, Bioreactor fluid dynamics, in: Proc. 2nd Bioreactor Conf., Cambridge, UK, BHRA (1988), pp. 37–64.Google Scholar
- 12.B. Mazzarotta, Comminution phenomena in stirred sugar suspensions, AIChE Symp. Ser., 89,112–117 (1993).Google Scholar
- 16.F. Grisafi, A. Brucato, and L. Rizzuti, Solid–liquid mass transfer coefficient in mixing tanks: influence of side wall roughness, IChemE Symp. Ser., 136, 571–578 (1994).Google Scholar
- 34.S. Nagata, Mixing, Principles and Applications, Halsted Press, New York (1975).Google Scholar
- 37.A. W. Nienow, D. J. Wisdom, and J. C. Middleton, The effect of scale and geometry on flooding recirculation and power in gassed stirred vessels, in: Proc. 2nd Europ. Conf. Mixing, BHRA, Cranefield, U.K. (1977), paper F-l .Google Scholar
- 43.V. Ranade, Computational Flow Modeling for Chemical Reactor Engineering, Academic Press, San Diego, USA (2002).Google Scholar
- 46.A. Bakker and H. E. A. Van Den Akker, A computational model for the gas–liquid flow in stirred reactors, Trans. IChemE, 72, 594–606 (1994).Google Scholar