Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-10T05:38:15.595Z Has data issue: false hasContentIssue false
  • English
  • Français

Characterisation of acoustically linked oscillations in cyclone separators

Published online by Cambridge University Press:  02 September 2015

T. A. Grimble  and
A. Agarwal
T. A. Grimble
Affiliation:
Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
A. Agarwal*
Affiliation:
Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
*
†Email address for correspondence: aa406@cam.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

The hydrodynamic oscillations of a cyclone separator – in particular the precessing vortex core (PVC) phenomena – are investigated by measuring their radiated sound spectra. Strong coherence was observed between internal flow oscillations measured via hot wire anemometry and the external acoustic field measured via microphone. This means that the oscillations can be characterised by using acoustics as a proxy. The oscillations cause narrow-band noise, referred to as cyclone hum. System characterisation by dimensional analysis used velocity and length scales of the vortex core region as scaling parameters. The relevant non-dimensional parameters are a Strouhal number for the cyclone hum centre frequency, a Reynolds number, a geometry based swirl number and numerous geometric scales defining the shape of the device. Cyclones with multiple sizes of inlets and outlets were tested at different flow rates using external microphones to detect the cyclone hum. The results produce an excellent collapse of the data, yielding a simple relationship for Strouhal number as a function of swirl number and the outlet diameter ratio. The non-invasive method of examining oscillations that is presented in this paper could be applied to other swirling systems.

JFM classification

Acoustics: Aeroacoustics Vortex Flows: Vortex Flows Vortex Flows: Vortex instability
Type
Papers
Information
Journal of Fluid Mechanics , Volume 780 , 10 October 2015 , pp. 45 - 59
Check for updates
Copyright
© 2015 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Cassidy, J. J. & Falvey, H. T. 1970 Observations of unsteady flow arising after vortex breakdown. J. Fluid Mech. 41, 727–736.CrossRefGoogle Scholar
Chanaud, R. C. 1965 Observations of oscillatory motion in certain Swirling flows. J. Fluid Mech. 21, 111–127.CrossRefGoogle Scholar
Cortes, C. & Gil, A. 2007 Modeling the gas and particle flow inside cyclone separators. Prog. Energy Combust. Sci. 33 (5), 409–452.CrossRefGoogle Scholar
Gupta, A. K., Lilley, D. G. & Syred, N. 1984 Swirl Flows. Abaqus Press.Google Scholar
Health and Safety Executive 2013 Sound Solutions for the Food and Drink Industries: Reducing Noise in Food and Drink Manufacturing. Available online: http://www.hse.gov.uk/pubns/books/hsg232.htm.Google Scholar
Hoffmann, A. C. & Stein, L. E. 2007 Gas Cyclones and Swirl Tubes: Principles, Design, and Operation. Springer.Google Scholar
Martinelli, F., Olivani, A. & Coghe, A. 2007 Experimental analysis of the precessing vortex core in a free Swirling jet. Exp. Fluids 42 (6), 827–839.CrossRefGoogle Scholar
Peng, W., Hoffmann, A. C., Dries, H. W. A., Regelink, M. A. & Stein, L. E. 2005 Experimental study of the vortex end in centrifugal separators: the nature of the vortex end. Chem. Engng Sci. 60 (24), 6919–6928.CrossRefGoogle Scholar
Solero, G. & Coghe, A. 2002 Experimental fluid dynamic characterization of a cyclone chamber. Exp. Therm. Fluid Sci. 27, 87–96.CrossRefGoogle Scholar
Syred, N. 2006 A review of oscillation mechanisms and the role of the precessing vortex core (PVC) in Swirl combustion systems. Prog. Energy Combust. Sci. 32 (2), 93–161.CrossRefGoogle Scholar
Yazdabadi, P. A., Griffiths, A. J. & Syred, N. 1994a Characterization of the PVC phenomena in the exhaust of a cyclone dust separator. Exp. Fluids 17 (1–2), 84–95.CrossRefGoogle Scholar
Yazdabadi, P. A., Griffiths, A. J. & Syred, N. 1994b Investigations into the precessing vortex core phenomenon in cyclone dust separators. Proc. Inst. Mech. Engrs E 208 (25), 147–154.CrossRefGoogle Scholar