Corona Discharge Characteristics and Particle Losses in a Unipolar Corona-needle Charger Obtained through Numerical and Experimental Studies

  • Intra, Panich (Research Unit of Applied Electric Field in Engineering (RUEE), College of Integrated Science and Technology, Rajamangala University of Technology Lanna) ;
  • Yawootti, Artit (Research Unit of Applied Electric Field in Engineering (RUEE), College of Integrated Science and Technology, Rajamangala University of Technology Lanna) ;
  • Rattanadecho, Phadungsak (Center of Excellence in Electromagnetic Energy Utilization in Engineering (CEEE), Department of Mechanical Engineering, Faculty of Engineering, Thammasat University)
  • Received : 2016.09.06
  • Accepted : 2017.06.10
  • Published : 2017.09.01


In this paper, the unipolar corona-needle charger was developed and its capabilities were both numerically and experimentally investigated. The experimental corona discharges and particle losses in the charger were obtained at different corona voltage, aerosol flow rate and particle diameter for positive and negative coronas. Inside the charger, the electric field and charge distribution and the transport behavior of the charged particle were predicted by a numerical simulation. The experimental results yielded the highest ion number concentrations of about $1.087{\times}10^{15}ions/m^3$ for a positive corona voltage of about 3.2 kV, and $1.247{\times}10^{16}ions/m^3$ for a negative corona voltage of about 2.9 kV, and the highest $N_it$ product for positive and negative coronas was found to about $7.53{\times}10^{13}$ and $8.65{\times}10^{14}ions/m^3$ s was occurred at the positive and negative corona voltages of about 3.2 and 2.9 kV, respectively, and the flow rate of 0.3 L/min. The highest diffusion loss was found to occur at particles with diameter of 30 nm to be about 62.50 and 19.33 % for the aerosol flow rate of 0.3 and 1.5 L/min, respectively, and the highest electrostatic loss was found to occur at particles with diameters of 75 and 50 nm to be about 86.29 and 72.92 % for positive and negative corona voltages of about 2.9 and 2.5 kV, respectively. The numerical results for the electric field distribution and the charged particles migration inside the charger were used to guide the description of the electric field and the behavior of charged particle trajectories to improve the design and refinement of a unipolar corona-needle charger that otherwise could not be seen from the experimental data.


Corona discharge;Particle charging;Aerosol charger;Numerical simulation


Supported by : National Science and Technology Development Agency (NSTDA), Thailand Research Fund (TRF)


  1. J. Chang, A.J. Kelly, and J.M. Crowley, Handbook of Electrostatic Processes, Marcel Dekker, Inc., New York (1995).
  2. K.R. Parker, Applied Electrostatic Precipitation, Blackie Academic & Professional, New York (1997).
  3. P. Intra and N. Tippayawong, "An overview of unipolar charger developments for nanoparticle charging", Aerosol and Air Quality Research, vol. 11, no.2, pp. 186-208, 2011.
  4. P. Intra and N. Tippayawong, "Progress in unipolar corona discharger designs for airborne particle charging: a literature review", Journal of Electro-statics, vol. 67, no. 4, pp. 605-615, 2009.
  5. K. T. Whitby, "Generator for producing high concentration of small ions", Review of Scientific Instruments, vol. 32, no. 12, pp. 1351-1355, 1961.
  6. A. Medved, F. Dorman, S. L. Kaufman, and A. Pocher, "A new corona-based charger for aerosol particles", Journal of Aerosol Science, vol. 31, pp. s616-s617, 2000.
  7. A. Marquard, M. Kasper, J. Meyer, and G. Kasper, "Nanoparticle charging efficiencies and related charging conditions in a wire-tube ESP at DC energization", Journal of Electrostatics, vol. 63, pp. 693-698, 2005.
  8. A. Hernandez-Sierra, F. J. Alguacil, and M. Alonso, "Unipolar charging of nanometer aerosol particle in a corona ionizer", Journal of Aerosol Science, vol. 34 pp. 733-745, 2003.
  9. M. Alonso, M. I. Martin, and F. J. Alguacil, "The measurement of charging efficiencies and losses of aerosol nanoparticles in a corona charger", Journal of Electrostatics, vol. 64, pp. 203-214, 2006.
  10. D. Park, M. An and J. Hwang, "Development and performance test of a unipolar diffusion charger for real-time measurements of submicron aerosol particles having a log-normal size distribution", Journal of Aerosol Science, vol. 38, no. 4, 420-430, 2007.
  11. C.L. Chien, C.J. Tsai, H.L. Chen, G.Y. Lin, and J.S. Wu, "Modeling and validation of nanoparticle charging efficiency of a single-wire corona unipolar charger", Aerosol Science and Technology, vol. 45, pp. 1468-1479, 2011.
  12. A. Marquard, J. Meyer, and G. Kasper, "Characterization of unipolar electrical aerosol chargers-Part II: Application of comparison criteria to various types of nanoaerosol charging devices", Journal of Aerosol Science, vol. 37, pp. 1069-1080, 2006.
  13. C. Qi, D. R. Chen, and P. Greenberg, "Performance study of a unipolar aerosol mini-charger for a personal nanoparticle sizer", Journal of Aerosol Science, vol. 39 450-459, 2008.
  14. P. Intra and N. Tippayawong, "Effect of needle cone angle and air flow rate on electrostatic discharge characteristics of a corona-needle ionizer". Journal of Electrostatics, vol. 68, no. 3, pp. 254-260, 2010.
  15. P. Intra and N. Tippayawong, "Design and evaluation of a high concentration, high penetration unipolar corona ionizer for electrostatic discharge and aerosol charging", Journal of Electrical Engineering and Technology, vol. 8, no. 5, pp. 1175-1181, 2013.
  16. COMSOL Inc., COMSOL Multi Physics Modelling Guide, Version 3.5a (2008).
  17. H. J. White, Industrial Electrostatic Precipitation, Addison-Wesley, Reading, Massachusetts (1963).
  18. W. C. Hinds, Aerosol Technology, John Wiley & Sons, New York, USA, 1999.
  19. G. P. Reischl, J.M. Makela, R. Harch, and J. Necid, "Bipolar charging of ultrafine particles in the size range below 10 nm", Journal of Aerosol Science, vol. 27, no. 6, pp. 931-939, 1996.
  20. C. J. Tsai, G. Y. Lin, H. L. Chen, C. H. Hunag, and M. Alonso, "Enhancement of extrinsic charging efficiency of a nanoparticle charger with multiple discharging wires", Aerosol Science Technology, vol. 44, pp. 807-816, 2010.