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|Title: ||PIV study of the flow field generated by a sawtooth impeller|
|Authors: ||Unadkat, Heema|
Rielly, Chris D.
Nagy, Zoltan K.
|Keywords: ||Particle image velocimetry|
|Issue Date: ||2011|
|Publisher: ||© Elsevier|
|Citation: ||UNADKAT, H., RIELLY, C.D. and NAGY, Z.K., 2011. PIV study of the flow field generated by a sawtooth impeller. Chemical Engineering Science, 66 (21), pp. 5374-5387.|
|Abstract: ||Stereoscopic and high-speed particle image velocimetry (PIV) techniques have been
employed to study the flow field induced by a sawtooth (EkatoMizer) impeller,
operated in the fully turbulent flow regime at an impeller speed of 1500 rpm.
Ensemble-averaged mean flow fields and turbulence quantities were calculated for a
region close to the impeller blades. The flow was found to be anisotropic near the
impeller and exhibited return-to-isotropy behaviour further away from it. Macroinstabilities
were found to have a high probability of occurrence in the discharge
stream. All three velocity components from the stereo-PIV measurements were used
to estimate the dissipation rate, by adopting a large eddy simulation (LES) analogy.
Spurious vectors distorting the dissipation rate calculation were identified, and
various standard deviation filters were applied for vector validation. By evaluating the
filtered dissipation rate profiles against the multi-fractal intermittency model of
Meneveau and Sreenivasan (1991), the global standard deviation filter was found to
be the most suitable type. The ratio of the maximum to the mean dissipation rate for
the EkatoMizer discharge stream was found to be similar to that reported for
Rushton disk turbine and pitched-blade turbine impellers in the literature, raising
questions about the reported high-shear advantage of sawtooth impellers.|
|Description: ||This is the author’s version of a work that was accepted for publication in the journal Chemical Engineering Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published at: http://dx.doi.org/10.1016/j.ces.2011.07.046|
|Version: ||Accepted for publication|
|Publisher Link: ||http://dx.doi.org/10.1016/j.ces.2011.07.046|
|Appears in Collections:||Published Articles (Chemical Engineering)|
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