Reduced power consumption in stirred vessels by means of fractal impellers

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Title: Reduced power consumption in stirred vessels by means of fractal impellers
Author(s): Basbug, S
Papadakis, G
Vassilicos, C
Item Type: Journal Article
Abstract: Earlier studies have shown that the power consumption of an unbaffled stirred vessel decreases significantly when the regular blades are replaced by fractal ones. In this paper, the physical explanation for this reduction is investigated using Direct Numerical Simulations at Re = 1600. The gaps around the fractal blade perimeter create jets that penetrate inside the recirculation zone in the wake and break up the trailing vortices into smaller ones. This affects the time‐average recirculation pattern on the suction side. The volume of the separation region is 7% smaller in the wake of the fractal blades. The lower torque of the fractal impeller is equivalent to a decreased transport of angular momentum; this difference stems from the reduced turbulent transport induced by the smaller trailing vortices. The major difference in the turbulent dissipation is seen in the vicinity of trailing vortices, due to fluctuations of velocity gradients at relatively low frequencies.
Publication Date: 8-Feb-2018
Date of Acceptance: 24-Nov-2017
URI: http://hdl.handle.net/10044/1/58652
DOI: https://doi.org/10.1002/aic.16096
ISSN: 0001-1541
Publisher: Wiley
Start Page: 1485
End Page: 1499
Journal / Book Title: AIChE Journal
Volume: 64
Issue: 4
Sponsor/Funder: Commission of the European Communities
Funder's Grant Number: FP7 - 317269
Copyright Statement: © 2018 American Institute of Chemical Engineers. This is the accepted version of the following article: Başbuğ, S. , Papadakis, G. and Vassilicos, J. C. (2018), Reduced power consumption in stirred vessels by means of fractal impellers. AIChE J., 64: 1485-1499, which has been published in final form at https://doi.org/10.1002/aic.16096
Keywords: Science & Technology
Technology
Engineering, Chemical
Engineering
DNS
trailing vortices
radial impeller
power consumption
pressure coefficient
unbaffled
RUSHTON TURBINE
FLOW
TANK
EFFICIENCY
VORTEX
physics.flu-dyn
physics.flu-dyn
0904 Chemical Engineering
0914 Resources Engineering And Extractive Metallurgy
Chemical Engineering
Publication Status: Published
Embargo Date: 2019-02-08
Appears in Collections:Faculty of Engineering
Aeronautics



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