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 atmospheric air pressures, the proposed equivalent circuit model of the MHCD reactor could be generalized for other gases at different pressures.

Dissociation of carbon dioxide using a microhollow cathode discharge plasma reactor: effects of applied voltage, flow rate and concentration

“…This charging-discharging characteristic of the MHCD reactor resembles a capacitive behavior. Taylan and Berberoglu [37] reported the characterization and modeling of the current-voltage behavior of the MHCD plasma reactor in detail in the self-pulsing regime as a function of applied dc voltage. The authors modeled the MHCD reactor as a constant capacitor parallel with a variable negative differential resistor.…”

Effects of reactor geometry on dissociating CO2 and electrode degradation in a MHCD plasma reactor

“…As electrode degradation is attributed to ion and electron collisions with the electrode surface, the degradation rates in this study were expected to be related to electron density and energies in the reactor. As the reactor was operated in the self‐pulsing regime, the plasma expanded over the electrode around the hole from which charges were discharged in less than 20 ns . As the plasma expanded over the electrode, the electrode surface would degrade due to heating caused by ion impact on the electrode surface.…”

“…In MHCD reactors, there are different operating ranges based on current and voltage characteristics . In this study, DC voltage was applied to the reactor and current was limited by a ballast resistor to operate the reactor in the self‐pulsing regime, which is characterized by negative differential impedance.…”

“…In MHCD reactors, there are different operating ranges based on current and voltage characteristics. 51 In this study, DC voltage was applied to the reactor and current was limited by a ballast resistor to operate the reactor in the self-pulsing regime, which is characterized by negative differential impedance. In this regime, non-thermal plasma was generated, and thus heating of the gas and heavy ions, i.e., ions and neutral molecules, in the discharge hole was largely avoided.…”

“…As the reactor was operated in the self-pulsing regime, the plasma expanded over the electrode around the hole from which charges were discharged in less than 20 ns. 51 As the plasma expanded over the electrode, the electrode surface would degrade due to heating caused by ion impact on the electrode surface. A higher electrode degradation rate was therefore observed for the cases where higher charge number density and ion energies were expected.…”