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 pos...
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.
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.
* AI 자동 식별 결과로 적합하지 않은 문장이 있을 수 있으니, 이용에 유의하시기 바랍니다.
문제 정의
Rainer Zawadzki of Governor State University and Asst. Prof. Dr. Achariya Suriyawong, Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University for the valuable contribution during the preparation of the manuscript.
제안 방법
In this paper, a unipolar corona-needle charger was designed as well as numerically and experimentally investigated to determine the corona discharges and particle losses in the charger at different corona voltages, aerosol flow rates and particle diameters for positive and negative coronas. Using a commercial computational fluid dynamics software package, COMSOL MultiphysicsTM, the electric field and charge distribution and the charged particle transport behaviors inside the charger were predicted.
In this study, charged particles with diameters of 30, 50, 75, 100, 150 and 200 nm corresponding to particle masses of 6 × 10-16, 3 × 10-15, 6 × 10-15, 9 × 10-15, 1 × 10-14 and 2 × 10-14 g, respectively, were used to study the behavior of the charged particle trajectories in the charger.
It consisted of a corona-needle charger, an adjustable DC high voltage power supply, a Faraday cup, an electrometer, a high efficiency particulate-free air (HEPA) filter, an atomizer aerosol generator, a dilution chamber, a diffusion dryer, a charged particle removal, an electrostatic classifiers, an ultrafine condensation particle counter and a vacuum pump.
5 kV, respectively. Numerical simulation results of the electric field distribution and the charged particle migration inside the charger; showed good agreement with experimental results of the corona discharges and particle losses and can be used to support further improve, modify and refine the unipolar corona-needle charger. These results can be used as the proper operating conditions for the charger.
Particles were then classified according to their electrical mobility using an advanced aerosol neutralizer (model 3088, TSI, Inc., Shoreview, MN, USA) and an electrostatic classifier (EC, model 3080, TSI, Inc., Shoreview, MN, USA) with a long-differential mobility analyzer (long DMA, model 3081, TSI, Inc., Shoreview, MN, USA) allowing mobility diameter selection of monodisperse test particles from 30 to 200 nm.
An increase in electrostatic force on the charged particles produced a decrease in the penetration efficiency of the charged particles in the charger. These calculation results can be used to support the improvement of further modification and refinement of the charger and also to understand the mechanisms of the charged particle transport inside the charger.
In this paper, a unipolar corona-needle charger was designed as well as numerically and experimentally investigated to determine the corona discharges and particle losses in the charger at different corona voltages, aerosol flow rates and particle diameters for positive and negative coronas. Using a commercial computational fluid dynamics software package, COMSOL MultiphysicsTM, the electric field and charge distribution and the charged particle transport behaviors inside the charger were predicted. It was shown that the highest discharge currents of the charger were 9.
이론/모형
3 shows the mesh distribution for the flow and electric fields of the charger. The considered problem was discretized with the finite element method (FEM), and triangular elements for the axis-symmetric two-dimensional model were utilized. The mesh was automatically generated by COMSOL [10] and was refined in the critical regions such as the corona-needle electrode head and between outer electrode and insulators.
The mean of charge per particle was approximated by White’s charging equation for field and diffusion charging [17, 18].
Three partial differential equations (PDE) were selected and coupled in the commercial software package COMSOL MultiphysicsTM, namely, the Poisson’s and Navier-Stokes equations as well as the Khan and Richardson force to the accurate model of the corona-needle charger [16].
성능/효과
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 diameter 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. Numerical simulation results of the electric field distribution and the charged particle migration inside the charger; showed good agreement with experimental results of the corona discharges and particle losses and can be used to support further improve, modify and refine the unipolar corona-needle charger.
Therefore, the mean of charge per particle was 3.46, 6.21, 9.86, 13.65, 21.54 and 29.73 electrons for the charged particles with diameters of 30, 50, 75, 100, 150 and 200 nm, respectively, at the Nit product of 2.95 × 1013 ions/m3s, the corona voltage of 3 kV, the electric field strength of 4.27 × 104 V/m, and the dielectric constant of 3.0, respectively.
참고문헌 (20)
J. Chang, A.J. Kelly, and J.M. Crowley, Handbook of Electrostatic Processes, Marcel Dekker, Inc., New York (1995).
K.R. Parker, Applied Electrostatic Precipitation, Blackie Academic & Professional, New York (1997).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
COMSOL Inc., COMSOL Multi Physics Modelling Guide, Version 3.5a (2008).
H. J. White, Industrial Electrostatic Precipitation, Addison-Wesley, Reading, Massachusetts (1963).
W. C. Hinds, Aerosol Technology, John Wiley & Sons, New York, USA, 1999.
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.
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.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.