Abstract
Stirred tanks are typically used in many reactions. The quality of
mixing generated by the impellers can be determined using either
experimental and simulation methods, or both methods. The experimental
techniques have evolved from traditional approaches, such
as the application of hot-wire anemometry, to more modern ones
like laser Doppler velocimetry (LDV). Similarly, computational fluid
dynamics (CFD) simulation techniques have attracted a lot of
attention in recent years in the study of the hydrodynamics in
stirred tanks, compared to the empirical modelling approach.
Studies have shown that the LDV technique can provide very detailed
information on the spatio-temporal variations in a tank, but the
method is costly. For this reason, CFD simulation techniques may
be employed to provide such data at a lower cost. In recent years,
both integrated experimental and CFD approaches have been used
to determine flow field and to design various systems. Both CFD
and LDV data reveal the existence of flow maldistribution caused by
system design features, and these in turn show that the configurations
that have, over the years, been regarded as standard may not
provide the optimal operating conditions with regards to the system
homogeneity and power consumption. The current trends in CFD
studies point towards an increasing application of more refined
grids, such as in large eddy simulation, to capture turbulent structures
at microscales. This trend will further improve the quality of the
simulation results for processes such as precipitation, in which
micromixing and reaction kinetics are important.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:tut/oai:encore.tut.ac.za:d1001406 |
| Date | 05 November 2009 |
| Creators | Ochieng, A, Onyango, M, Kiriamiti, K |
| Publisher | South African Journal of Science |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | |
| Rights | South African Journal of Science |
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