Topical Problems of Fluid Mechanics


Institute of Thermomechanics AS CR, v.v.i.	CTU in Prague Faculty of Mech. Engineering Dept. Tech. Mathematics	MIO Université du Sud Toulon Var - AMU - CNRS - IRD	Czech Pilot centre ERCOFTAC

Improvement of an Unbaffled Stirred Tank Mixing Characteristics Using Variable Speed Impeller
Gebouský O., Haidl J., Bodnár J., Pivokonský M.
Abstract:
Unbaffled mixing tanks with magnetically driven impellers are increasingly used in biotechnological and pharmaceutical industries, combining the benefits of a closed, sterile environment with easy equipment cleanability. On the other hand, missing internals, such as baffles or cooling coils, have an adverse effect on the equipment mixing characteristics, namely the batch homogenization time. In our previous research, we uncovered that the eccentricity and inclination of the impeller – both employed routinely to enhance the mixing characteristics of unbaffled vessels – are not fully effective in the suppression of central vortex formation resulting in the increase in the homogenization time. In this work, we propose a simple solution to counteract the central vortex formation – a periodical variation of impeller rotational speed. This approach destabilizes the central vortex, significantly reducing homogenization time while maintaining the benefits of the original unbaffled setup. This innovation can seamlessly integrate into existing industrial setups, promising efficiency gains for biotech and pharmaceutical production.
Keywords:
unbaffled mixing tanks, variable rotational speed, vortex destabilization, mixing time improvement

Fulltext: PDF DOI: https://doi.org/10.14311/TPFM.2024.008

In Proceedings Topical Problems of Fluid Mechanics 2024, Prague, 2024, Edited by David Šimurda and Tomáš Bodnár, pp. 54 ISBN 978-80-87012-88-8 (Print) ISSN 2336-5781 (Print)