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Title: Electrical characterization and an equivalent circuit model of a microhollow cathode discharge reactor

Abstract

This paper reports the electrical characterization and an equivalent circuit of a microhollow cathode discharge (MHCD) reactor in the self-pulsing regime. A MHCD reactor was prototyped for air plasma generation, and its current-voltage characteristics were measured experimentally in the self-pulsing regime for applied voltages from 2000 to 3000 V. The reactor was modeled as a capacitor in parallel with a variable resistor. A stray capacitance was also introduced to the circuit model to represent the capacitance of the circuit elements in the experimental setup. The values of the resistor and capacitors were recovered from experimental data, and the proposed circuit model was validated with independent experiments. Experimental data showed that increasing the applied voltage increased the current, self-pulsing frequency and average power consumption of the reactor, while it decreased the peak voltage. The maximum and the minimum voltages obtained using the model were in agreement with the experimental data within 2.5%, whereas the differences between peak current values were less than 1%. At all applied voltages, the equivalent circuit model was able to accurately represent the peak and average power consumption as well as the self-pulsing frequency within the experimental uncertainty. Although the results shown in this paper was for atmosphericmore » air pressures, the proposed equivalent circuit model of the MHCD reactor could be generalized for other gases at different pressures.« less

Authors:
;  [1]
  1. Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)
Publication Date:
OSTI Identifier:
22308922
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AIR; CAPACITANCE; CAPACITORS; CURRENTS; ELECTRIC POTENTIAL; EQUIVALENT CIRCUITS; PLASMA; PULSES; RESISTORS; SIMULATION

Citation Formats

Taylan, O., and Berberoglu, H., E-mail: berberoglu@mail.utexas.edu. Electrical characterization and an equivalent circuit model of a microhollow cathode discharge reactor. United States: N. p., 2014. Web. doi:10.1063/1.4891250.
Taylan, O., & Berberoglu, H., E-mail: berberoglu@mail.utexas.edu. Electrical characterization and an equivalent circuit model of a microhollow cathode discharge reactor. United States. doi:10.1063/1.4891250.
Taylan, O., and Berberoglu, H., E-mail: berberoglu@mail.utexas.edu. Mon . "Electrical characterization and an equivalent circuit model of a microhollow cathode discharge reactor". United States. doi:10.1063/1.4891250.
@article{osti_22308922,
title = {Electrical characterization and an equivalent circuit model of a microhollow cathode discharge reactor},
author = {Taylan, O. and Berberoglu, H., E-mail: berberoglu@mail.utexas.edu},
abstractNote = {This paper reports the electrical characterization and an equivalent circuit of a microhollow cathode discharge (MHCD) reactor in the self-pulsing regime. A MHCD reactor was prototyped for air plasma generation, and its current-voltage characteristics were measured experimentally in the self-pulsing regime for applied voltages from 2000 to 3000 V. The reactor was modeled as a capacitor in parallel with a variable resistor. A stray capacitance was also introduced to the circuit model to represent the capacitance of the circuit elements in the experimental setup. The values of the resistor and capacitors were recovered from experimental data, and the proposed circuit model was validated with independent experiments. Experimental data showed that increasing the applied voltage increased the current, self-pulsing frequency and average power consumption of the reactor, while it decreased the peak voltage. The maximum and the minimum voltages obtained using the model were in agreement with the experimental data within 2.5%, whereas the differences between peak current values were less than 1%. At all applied voltages, the equivalent circuit model was able to accurately represent the peak and average power consumption as well as the self-pulsing frequency within the experimental uncertainty. Although the results shown in this paper was for atmospheric air pressures, the proposed equivalent circuit model of the MHCD reactor could be generalized for other gases at different pressures.},
doi = {10.1063/1.4891250},
journal = {Journal of Applied Physics},
number = 4,
volume = 116,
place = {United States},
year = {Mon Jul 28 00:00:00 EDT 2014},
month = {Mon Jul 28 00:00:00 EDT 2014}
}
  • This paper describes how to light several microdischarges in parallel without having to individually ballast each one. The V-I curve of a microhollow cathode discharge is characterized by a constant voltage in the normal glow regime because the plasma is able to spread over the cathode surface area to provide the additional secondary electrons needed. If one limits the cathode surface area, the V-I characteristic can be forced into an abnormal glow regime in which the operating voltage must increase with the current. It is then possible to light several microdischarges mounted in parallel without ballasting them individually.
  • Microhollow cathode discharges are high-pressure, nonequilibrium gas discharges between a hollow cathode and a planar or hollow anode with electrode dimensions in the 100 {mu}m range. The large concentration of high-energy electrons, in combination with the high-gas density favors excimer formation. Excimer emission was observed in xenon and argon, at wavelengths of 128 and 172 nm, respectively, and in argon fluoride and xenon chloride, at 193 and 308 nm. The radiant emittance of the excimer radiation was found to increase monotonically with pressure. However, due to the decrease in source size with pressure, the efficiency (ratio of excimer radiant powermore » to input electrical power), has for xenon and argon fluoride a maximum at {approx}400 Torr. The maximum efficiency is between 6% and 9% for xenon, and {approx}2% for argon fluoride. (c) 2000 American Institute of Physics.« less
  • Microhollow cathode discharges (MHCD's) are miniature direct-current discharges that operate at elevated pressures (several tens to hundreds of Torr) with electrode dimensions in the 10-100-{mu}m range. MHCD's have been proposed for a number of applications based on their unique characteristics such as presence of intense excimer radiation and significant gas heating within the submillimeter discharge volume. A two-dimensional, self-consistent fluid model of a helium MHCD in the high-pressure (several hundreds of Torr), high-current ({approx}1 mA) operating regime is presented in this study. Results indicate that the MHCD operates in an abnormal glow discharge mode with charged and excited metastable speciesmore » with densities of {approx}10{sup 20} m{sup -3}, electron temperatures of approximately tens of eV, and gas temperatures of hundreds of Kelvin above room temperature. Significant discharge activity exists outside of the hollow region. The discharge volume and intensity increases with increasing current and becomes more confined with increasing pressures. Most predictions presented in this paper are in qualitative and quantitative agreement with experimental data for MHCD's under similar conditions.« less
  • The authors introduced a concept of self-sensing neutralization system by means of automatically ejected charged particles from alternative current microhollow cathode discharge. When the positive bias was applied to the third electrode, a real current flow was only detected during negative polarity period of voltage applied to the first electrode. On the other hand, in the case of negative bias, there was only the real current during positive polarity period. These results mean that our system shows simultaneously the self-sensing and then neutralizing characteristics in a period.
  • We introduce a microhollow cathode configuration with venturi gas flow to ambient air in order to obtain glow discharge at atmospheric pressure. Stable microhollow cathode discharge was formed in a 200 {mu}m diameter at 9 mA and the optimum value of gas velocityxdiameter for hollow cathode effect was obtained in our system. In order to confirm hollow cathode effect, we measured the enhancement of E/N strength for 200 {mu}m (0.31 m{sup 2}/s) and 500 {mu}m (0.78 m{sup 2}/s) air discharge at 8 mA under the velocity of 156 m/s. As a result, an increase of 46.7% in E/N strength ofmore » the discharge of 200 {mu}m hole was obtained compare to that of 500 {mu}m.« less