Analysis of the critical active species for methylene blue decoloration in a dielectric barrier discharge plasma system

Wang, Huijuan; Mao, Danni; Cao, Wudi; Yan, Xin

doi:10.1088/2058-6272/aba345

Cited by 11 publications

(1 citation statement)

References 41 publications

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“…Two circular parallel plate electrodes, each covered with the dielectric plates of relative permittivity (ò r = 7.5), are connected to a sinusoidal voltage source. The dielectric constant of 7.5 corresponds to mica glass which is one of the most commonly used dielectric materials in DBD reactors [40][41][42]. Dielectric plates with millimeter-range thickness are commonly used in parallel plate DBD reactor setups like the one used in our research [14,[43][44][45].…”

Section: Operational Parameters and Geometrymentioning

confidence: 99%

Pre-breakdown to stable phase and origin of multiple current pulses in argon dielectric barrier discharge

Gautam¹,

Morra²

2021

Plasma Sci. Technol.

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We report on the results of numerical models of the (i) initial growth and (ii) steady state phases of atmospheric-pressure homogeneous dielectric barrier discharge in argon. We employ our new in-house code called PyDBD, which solves continuity equations for both particles and energy, shows exceptional stability, is accelerated by adaptive time stepping and is openly available to the scientific community. Modeling argon plasma is numerically challenging due to the lower speeds of more inertial ions compared to more commonly modeled neon and helium, but its common use for plasma jets in medicine makes its modeling compelling. PyDBD is here applied to modeling two setups: (i) the exponential growth from natural electron-ion seeds (onset phase) until saturation is reached and (ii) the multiple current pulses that naturally appear during the steady state phase. We find that the time required for the onset phase, when the plasma density grows from 109 m−3 to 1017 m−3, varies from 80 μs at 4.5 kV down to a few μs above 6.5 kV, for voltage frequency f = 80 kHz and gap width d g = 0.9 mm. At the steady state, our model reproduces two previously observed features of the current in dielectric barrier discharge reactors: (1) an oscillatory behavior associated to the capacitative character of the circuit and (2) several (N p) current pulses occurring every half sinusoidal cycle. We show that the oscillations are present during the exponential growth, while current pulses appear approaching the steady state. After each micro-discharge, the gas voltage decreases abruptly and charged particles rapidly accumulate at the dielectric boundaries, causing avalanches of charged particles near the reactor boundaries. Finally, we run a parametric study finding that N p increases linearly with voltage amplitude V amp, is inversely proportional to dielectric gap d g and decreases when voltage frequency f increases. The code developed for this publication is freely available at the address https://github.com/gabersyd/PyDBD.

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