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Neutralization of a spray of electrically charged droplets by a corona discharge

Published online by Cambridge University Press:  19 July 2016

F. J. Higuera
F. J. Higuera*
Affiliation:
ETSIAE, Universidad Politécnica de Madrid, Plaza Cardenal Cisneros 3, 28040 Madrid, Spain
*
†Email address for correspondence: fhiguera@aero.upm.es
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Abstract

The neutralization of a dilute spray of electrically charged droplets by ions of the opposite polarity generated by a corona discharge at a wire ring is analysed numerically. A Lagrangian description of the spray and Eulerian descriptions of the gas and the ions are used to deal with this two-way coupled problem. A model of the corona consisting of a line of charge and a distribution of ion sources is proposed. In the configuration that is analysed, neutralization usually begins at the shroud of the spray and extends to inner regions when the corona current increases. The number density of droplets is large at the shroud due to neutralized droplets that are no longer pushed by the electric field. These droplets can be dragged towards a collector surface by a weak forced flow that overcomes the ionic wind due to the force of the ions on the gas. The fraction of the spray charge that is neutralized increases with the corona current, but the value of this current required for full neutralization is several times larger than the inlet electric current of the spray owing to loss of ions to the boundaries of the system. The electric field induced by the charge of the droplets opposes the field due to the voltage applied between the wire ring and the extractor through which the droplets are injected, and thus reduces the threshold voltage of the corona and significantly affects its current–voltage characteristic, which may become multivalued. In turn, the electric field due to the applied voltage and the space charge of the ions affects the shape of the spray and the velocity of the droplets.

JFM classification

Drops and Bubbles: Electrohydrodynamic effects Multiphase and Particle-laden Flows: Multiphase and Particle-laden Flows Multiphase and Particle-laden Flows: Particle/fluid flow
Type
Papers
Information
Journal of Fluid Mechanics , Volume 801 , 25 August 2016 , pp. 130 - 149
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Copyright
© 2016 Cambridge University Press 

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References

Adachi, M., Pui, D. Y. H. & Liu, B. Y. H. 1993 Aerosol charge neutralization by a corona ionizer. Aerosol Sci. Technol. 18, 48–58.CrossRefGoogle Scholar
Arumugham-Achari, A. K., Grifoll, J. & Rosell-Llompart, J. 2013 Two-way coupled numerical simulation of electrospray with induced gas flow. J. Aerosol Sci. 65, 121–133.CrossRefGoogle Scholar
Birdsall, C. K. & Langdon, A. B. 1991 Plasma Physics Via Computer Simulation. Taylor & Francis.CrossRefGoogle Scholar
Deng, W. & Gomez, A. 2007 Influence of space charge in the scale-up of multiplexed electrosprays. J. Aerosol Sci. 38, 1062–1078.CrossRefGoogle Scholar
Ebeling, D. D., Westphall, M. S., Scalf, M. & Smith, L. M. 2000 Corona discharge in charge reduction electrospray mass spectrometry. Anal. Chem. 72, 5158–5161.CrossRefGoogle ScholarPubMed
Fernández de la Mora, J. 2007 The fluid dynamics of Taylor cones. Annu. Rev. Fluid Mech. 39, 217–243.CrossRefGoogle Scholar
Friedlander, S. K. 2000 Smoke, Dust, and Haze. Fundamentals of Aerosol Dynamics. Oxford University Press.Google Scholar
Fuchs, N. A. 1989 The Mechanics of Aerosols. Dover.Google Scholar
Higuera, F. J. 2016 Dispersion and vaporization of a dilute spray of electrified droplets injected in a coflowing hot gas – application to the vaporization chamber of a minicombustor. J. Aerosol Sci. 91, 78–93.CrossRefGoogle Scholar
Hinch, E. J. 1991 Perturbation Methods. Cambridge University Press.CrossRefGoogle Scholar
Hinds, W. C. & Kennedy, N. J. 2000 An ion generator for neutralizing concentrated aerosols. Aerosol Sci. Technol. 32, 214–220.CrossRefGoogle Scholar
Hockney, R. W. & Eastwood, J. W. 1988 Computer Simulation Using Particles. Taylor & Francis.CrossRefGoogle Scholar
Ijsebaert, J. C., Geerse, K. B., Marijnissen, J. C. M., Lammers, J.-W. J. & Zanen, P. 2001 Electro-hydrodynamic atomization of drug solutions for inhalation purposes. J. Appl. Physiol. 91, 2735–2741.CrossRefGoogle ScholarPubMed
Intra, P. & Tippayawong, N. 2009 Progess in unipolar corona discharger design for airborne particle charging: a literature rewiew. J. Electrostat. 67, 605–615.CrossRefGoogle Scholar
Kallio, G. A. & Stock, D. E. 1992 Interaction of electrostatic and fluid dynamic fields in wire–plate electrostatic precipitators. J. Fluid Mech. 240, 133–166.CrossRefGoogle Scholar
Landau, L. D. & Lifshitz, E. M. 1960 Electrodynamics of Continuous Media. Pergamon.Google Scholar
Leonard, G. L., Mitchner, M. & Self, S. A. 1983 An experimental study of the electrohydrodynamic flow in electrostatic precipitators. J. Fluid Mech. 127, 123–140.CrossRefGoogle Scholar
Loeb, L. B. 1965 Electrical Coronas. University of California Press.CrossRefGoogle Scholar
Lu, Q. & Koropchak, J. A. 2004 Corona discharge neutralizer for electrospray aerosols used with condensation nucleation light-scattering detection. Anal. Chem. 76, 5539–5546.CrossRefGoogle ScholarPubMed
Meesters, G. M. H., Vercoulen, P. H. W., Marijnissen, J. C. M. & Scarlett, B. 1992 Generation of micron-sized droplets from the Taylor cone. J. Aerosol Sci. 23, 37–49.CrossRefGoogle Scholar
Raizer, Y. P. 1997 Gas Discharge Physics, 2nd edn. Springer.Google Scholar
Romay, F. J., Liu, B. Y. H. & Pui, D. Y. H. 1994 A sonic jet corona ionizer for electrostatic discharge and aerosol neutralization. Aerosol Sci. Technol. 20, 31–41.CrossRefGoogle Scholar
Sánchez, A., Urzay, J. & Liñán, A. 2015 The role of separation of scales in the description of spray combustion. Proc. Combust. Inst. 35, 1549–1577.CrossRefGoogle Scholar
Whitby, K. T. 1961 Generator for producting high concentrations of small ions. Rev. Sci. Instrum. 32, 1351–1355.CrossRefGoogle Scholar
Whitby, K. T. & Peterson, C. M. 1965 Neutralization and particle size measurement of dye aerosols. Ind. Engng Chem. Fundam. 4, 66–72.CrossRefGoogle Scholar
White, H. J. 1963 Industrial Electrostatic Precipitation. Addison-Wesley.Google Scholar
Williams, F. A. 1985 Combustion Theory, 2nd edn. Benjamin Cummings.Google Scholar
Yamamoto, T. & Velkoff, H. R. 1981 Electrohydrodynamics in an electrostatic precipitator. J. Fluid Mech. 108, 1–18.CrossRefGoogle Scholar
Zhao, L. & Adamiak, K. 2005 EHD flow in air produced by electric corona discharge in pin–plate configuration. J. Electrostat. 63, 337–350.CrossRefGoogle Scholar