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JEET, Vol. 12, No. 5, September 2017
Corona Discharge Characteristics and Particle Losses in a Unipolar Corona-needle Charger Obtained through Numerical and Experimental Studies
Panich Intra
Area C - Electrophysics and Applications
Abstract 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 1015 ions/m3 for a positive corona voltage of about 3.2 kV, and 1.247 1016 ions/m3 for a negative corona voltage of about 2.9 kV, and the highest Nit product for positive and negative coronas was found to about 7.53 1013 and 8.65 1014 ions/m3 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 coronaneedle charger that otherwise could not be seen from the experimental data.
Keyword Corona discharge,Particle charging,Aerosol charger,Numerical simulation
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