Hostname: page-component-5d84bcc8dc-zkzgt Total loading time: 0 Render date: 2026-09-13T20:16:56.254Z Has data issue: false hasContentIssue false
  • English
  • Français

Local linear stability analysis of cyclone separators

Published online by Cambridge University Press:  08 March 2017

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

Abstract

Local linear stability analysis is applied to the flow inside a cyclone separator to investigate the unsteady precession of the vortex core. The results of the stability analysis are compared with experimental measurements of the vortex oscillations using high-speed photography with particle seeding and hot-wire anemometry. The experiments reveal distinct spatial variation in the oscillation behaviour within the cyclone. The unsteady motion is focused at each end of the device, at both the narrow cone tip and just below the exhaust duct at the top of the cone, which is known as a vortex finder. The local stability analysis shows that an absolute instability is present throughout the flow for some non-zero azimuthal wavenumbers. The unsteady flow is observed to be driven by coupling between the shear layer and inertial waves confined within the vortex core. Comparison of the stability analysis with experiments shows the same frequency and mode shape behaviour and suggests that the local analysis accurately predicts the unstable modes of the system. The precessing vortex core is responsible for a narrow-band acoustic noise. Comparisons are also drawn with acoustic measurements made on cyclones in which the system is defined by key non-dimensional parameters, such as the swirl number and outlet diameter ratio. The results in this study demonstrate the applicability of local stability analysis to a complex swirling system and yield credible details about the underlying mechanisms of the unstable flow inside the cyclone.

JFM classification

Instability: Absolute/convective instability Acoustics: Hydrodynamic noise Vortex Flows: Vortex instability

Information

Type
Papers
Information
Journal of Fluid Mechanics , Volume 816 , 10 April 2017 , pp. 507 - 538
Check for updates
Copyright
© 2017 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.)

Article purchase

Temporarily unavailable

References

ANSYS2011 FLUENT Theory Guide Release 14.0.Google Scholar
Bers, A. 1983 Space–time evolution of plasma instabilities – absolute and convective. In Basic Plasma Physics (ed. Galeev, A. A. & Sudan, R. N.), vol. 1. Elsevier.Google 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.Google Scholar
Derksen, J. J. & Van den Akker, H. E. A. 2000 Simulation of vortex core precession in a reverse-flow cyclone. AIChE J. 46 (7), 1317–1331.Google Scholar
Gallaire, F. & Chomaz, J.-M. 2003 Instability mechanisms in swirling flows. Phys. Fluids 15, 2622–2639.CrossRefGoogle Scholar
Gimbun, J., Chuah, T. G., Choong, T. S. Y. & Fakhru’l-Razi, A. 2005 A CFD study on the prediction of cyclone collection efficiency. Intl J. Comput. Meth. Engng Sci. Mech. 6 (3), 161–168.Google Scholar
Grimble, T. A. & Agarwal, A. 2015 Characterisation of acoustically linked oscillations in cyclone separators. J. Fluid Mech. 780, 45–59.CrossRefGoogle Scholar
Gronald, G. & Derksen, J. J. 2011 Simulating turbulent swirling flow in a gas cyclone: a comparison of various modeling approaches. Powder Technol. 205, 160–171.CrossRefGoogle Scholar
Gupta, A. K., Lilley, D. G. & Syred, N. 1984 Swirl Flows. Abaqus Press.Google Scholar
Hoekstra, A. J., Derksen, J. J. & Van Den Akker, H. E. A. 1999 An experimental and numerical study of turbulent swirling flow in gas cyclones. Chem. Engng Sci. 54, 2055–2065.CrossRefGoogle Scholar
Huerre, P. 2000 Open shear flow instabilities. In Perspectives in Fluid Dynamics (ed. Batchelor, G. K., Moffatt, H. K. & Worster, M. G.), pp. 159–229. Cambridge University Press.Google Scholar
Huerre, P. & Monkewitz, P. A. 1990 Local and global instabilities in spatially developing flows. Annu. Rev. Fluid Mech. (22), 473–537.Google Scholar
Juniper, M. P.2012 Absolute and convective instability in gas turbine fuel injectors. Proceedings of ASME Turbo Expo 2012: Power for Land, Sea and Air.CrossRefGoogle Scholar
Juniper, M. P., Tammisola, O. & Lundell, F. 2011 The local and global stability of confined planar wakes at intermediate Reynolds number. J. Fluid Mech. 686, 218–238.CrossRefGoogle Scholar
Loiseleux, T., Chomaz, J. M. & Huerre, P. 1998 The effect of swirl on jets and wakes: linear instability of the Rankine vortex with axial flow. Phys. Fluids 10 (5), 1120–1134.CrossRefGoogle Scholar
Meliga, P., Pujals, G. & Serre, E. 2012 Sensitivity of 2-D turbulent flow past a D-shaped cylinder using global stability. Phys. Fluids 24, 061701.CrossRefGoogle Scholar
Mettot, C., Sipp, D. & Bézard, H. 2014 Quasi-laminar stability and sensitivity analyses for turbulent flows: prediction of low-frequency unsteadiness and passive control. Phys. Fluids 26, 045112.Google Scholar
Oberleithner, K., Sieber, M., Nayeri, C. N., Paschereit, C. O., Petz, C., Hege, H.-C., Noack, B. R. & Wygnanski, I. 2011 Three-dimensional coherent structures in a swirling jet undergoing vortex breakdown: stability analysis and empirical mode construction. J. Fluid Mech. 679, 383–414.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, 6919–6928.CrossRefGoogle Scholar
Pier, B. 2008 Local and global instabilities in the wake of a sphere. J. Fluid Mech. 603, 39–61.CrossRefGoogle Scholar
Pisarev, G. I., Gjerde, V., Balakin, B. V., Hoffmann, A. C., Dijkstra, H. A. & Peng, W. 2012 Experimental and computational study of the end of the vortex phenomenon in reverse-flow centrifugal separators. AIChE J. 58, 1371–1380.Google Scholar
Qadri, U. A., Mistry, D. & Juniper, M. P. 2013 Structural sensitivity of spiral vortex breakdown. J. Fluid Mech. 720, 558–581.Google Scholar
Rayleigh Lord 1916 On the dynamics of revolving fluids. Proc. R. Soc. Lond. 93 (648), 148–154.Google Scholar
Reynolds, W. C. & Hussain, A. K. M. F. 1972 The mechanics of an organized wave in turbulent shear flow. Part 3. Theoretical models and comparisons with experiments. J. Fluid Mech. 54, 263–288.Google Scholar
Saffman, P. G. 1992 Vortex Dynamics. Cambridge University Press.Google Scholar
Saric, W. S. 1994 Görtler vortices. Annu. Rev. Fluid Mech. 26, 379–409.Google Scholar
Slack, M. D., Prasad, R. O., Bakker, A. & Boysan, F. 2000 Advances in cyclone modelling using unstructured grids. Chem. Engng Res. Des. 78, 1098–1104.Google 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, 93–161.CrossRefGoogle Scholar
Tammisola, O.2011 Numerical stability studies of one-phase and immiscible two-phase jets and wakes. PhD thesis, KTH, Sweden.Google Scholar
Tammisola, O. & Juniper, M. P. 2016 Coherent structures in a swirl injector at Re = 4800 by nonlinear simulations and linear global modes. J. Fluid Mech. 792, 620–657.Google Scholar
Turton, S. E., Tuckerman, L. & Barkley, D. 2015 Prediction of frequencies in thermosolutal convection from mean flows. Phys. Rev. E 91, 043009.Google ScholarPubMed
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, 84–95.Google 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, 147–154.CrossRefGoogle Scholar