Numerical simulation of the effect of water admixtures on the evolution of a helium/dry air discharge

Lazarou, Constantinos; Chiper, Alina Silvia; Anastassiou, Charalambos; Topală, Ionuț; Mihăilă, Ilarion; Pohoaţǎ, Valentin; Georghiou, George E.

doi:10.1088/1361-6463/ab06cd

Cited by 19 publications

(28 citation statements)

References 103 publications

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“…where ρ represents the density of the mixture, ω n , n , and S n represent the mass fraction, the diffusive flux vector and the source term of the corresponding nth heavy particle, respectively. The mobility and diffusion coefficients of heavy particles considered in our model are taken from [29]- [31]. Q represents the number of total species of heavy particles.…”

Section: Plasma Model Descriptionmentioning

confidence: 99%

“…They proposed that due to the strong electronegativity of O 2 , anions are formed and the attachment of electrons would reduce the effective ionization, thereby influencing the ignition of the discharge and other discharge characteristics. In addition, taking the air impurities (both N 2 and O 2 ) into account, Lazarou et al found that the main cations are O + 2 and O + 4 when the air content reaches 500 ppm, and Penning ionization of O 2 with metastable states of helium is the main pathway for the electron generation in this situation [29]. Therefore, according to the basic physical understanding and the abovementioned reports, we should be more prudential to deal with the role of oxygen in atmospheric helium HDBDs with air impurities.…”

Section: Introductionmentioning

confidence: 99%

“…Although several publications have considered the air impurities when performing the simulation works [29]- [32], the detailed evolution mechanism regarding the influence of O 2 in air impurities on the MCP discharge characteristics, such as the dominant effect between N 2 and O 2 , or the difference of considering O 2 compared with previous evolution mechanism only with N 2 impurity [23], have not been investigated yet. Thus, the aim of this paper is to purposely study the influence of oxygen on the MCP behavior in an atmospheric helium HDBD with air impurities (79% N 2 and 21% O 2 ).…”

Section: Introductionmentioning

confidence: 99%

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Influence of Oxygen on the Multiple-Current-Pulse Behavior in an Atmospheric Homogeneous Helium Dielectric Barrier Discharge With Air Impurities

Luo¹,

Huang²,

Wang³

et al. 2020

IEEE Access

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In this paper, through a one-dimensional fluid model, we investigate the influence of oxygen on the multiple-current-pulse (MCP) behavior in an atmospheric homogeneous dielectric barrier discharge (HDBD) in helium with air impurities. From the simulation results, we find that the O 2 Penning ionization plays a leading role in the discharge characteristics. As the air content increases from 0 ppm to 5000 ppm, the current waveforms show a transition from a single-pulse mode to MCP mode, and the number of current pulses (N p) also increases. Through analysis, we find that although N p increases monotonically, the evolution mechanism of the MCP discharges under different ranges of air content is different. At lower air concentration (less than 500 ppm here), we find the similar explanation as that reported in our previous work on the MCP behavior only considering N 2 impurity. However, when the air content is higher, we find that the seed electron density (n e0) remains basically unchanged, not like the sharp drop at lower air concentration. Further analysis reveals that the rapid growth of direct ionization during a small period before the breakdown helps generate MCP discharges. In addition, the attachment reaction of O 2 is analyzed. Results show that at higher air content (above 5000 ppm here), the O 2 attachment reaction will provide more possibilities of successive ignitions after the first pulse with the assistance of the applied voltage, implying a stimulative effect of the oxygen on MCP discharges. INDEX TERMS Dielectric barrier discharge, fluid model, helium/air, multiple-current-pulse behavior.

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Section: Plasma Model Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Oxygen on the Multiple-Current-Pulse Behavior in an Atmospheric Homogeneous Helium Dielectric Barrier Discharge With Air Impurities

Luo¹,

Huang²,

Wang³

et al. 2020

IEEE Access

View full text Add to dashboard Cite

show abstract

“…In the 1-D fluid model, electron properties, including the electron density and energy density, are governed by the Boltzmann equation under drift-diffusion approximation [23][24][25], as given by Equation (1-4); Equation (5) and Equation (6) are multi-component transport equations [26,27] determining the flux of heavy species. Besides, in order to determine the electric field distribution, Poisson's equation is firmly coupled.…”

Section: Model Descriptionmentioning

confidence: 99%

A Practical Method for Controlling the Asymmetric Mode of Atmospheric Dielectric Barrier Discharges

et al. 2020

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Atmospheric pressure dielectric barrier discharges (DBDs) have been applied in a very broad range of industries due to their outstanding advantages. However, different discharge modes can influence the stability of atmospheric DBDs, such as the density and composition of active species in discharge plasmas, thereby impacting the effect of related applications. It is necessary and valuable to investigate the control of nonlinear modes both in theoretical and practical aspects. In this paper, we propose a practical, state-controlling method to switch the discharge mode from asymmetry to symmetry through changing frequencies of the applied voltage. The simulation results show that changing frequencies can effectively alter the seed electron level at the beginning of the breakdown and then influence the subsequent discharge mode. The higher controlling frequency is recommended since it can limit the dissipative process of residual electrons and is in favor of the formation of symmetric discharge in the after-controlling section. Under our simulation conditions, the discharges with an initial driving frequency of 14 kHz can always be converted to the symmetric period-one mode when the controlling frequency is beyond 30 kHz.

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“…A self‐consistent fluid model is developed within the plasma module of COMSOL® Multiphysics software. The detailed model equations have been thoroughly described in many previous studies, so here just some brief introductions are presented. In the model, the governing equations of electron properties are derived from the Boltzmann equation under the drift‐diffusion approximation, as given in Equations –, and the transport property of heavy species is solved by multicomponent transport equations, as given in Equations and :

\frac{\partial n_{normale}}{\partial t} + \nabla \cdot {bold-italicΓ}_{normale} = S_{normale},

\frac{\partial n_{normalε}}{\partial t} + \nabla \cdot {bold-italicΓ}_{bold-italicε} + E {bold-italicΓ}_{bold-italice} = S_{en},

{bold-italicΓ}_{normale} = - μ_{normale} n_{normale} E - D_{normale} \nabla \cdot n_{normale},

{bold-italicΓ}_{bold-italicε} = - \frac{5}{3} μ_{normale} n_{normalε} E - \frac{5}{3} D_{normale} \nabla \cdot n_{normalε},

ρ \frac{\partial ω_{k}}{\partial t} = \nabla \cdot {bold-italicJ}_{k} + S_{k},

{bold-italicJ}_{k} = ρ ω_{k} true(D_{k} \frac{\nabla ω_{k}}{ω_{k}} + D_{k} \frac{\nabla M_{n}}{M_{n}} - z_{k} μ_{k} E <...>

…”

Section: Model Descriptionmentioning

confidence: 99%

How does the moderate wavy surface affect the discharge behavior in an atmospheric helium dielectric barrier discharge model?

Wang

Ning

Dai

et al. 2019

Plasma Processes & Polymers

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A conventional parallel-plate dielectric barrier discharge (DBD) model but with one dielectric layer having a wavy surface is purposely built for better understanding the plasma-surface interaction. The results of simulation under a kilohertz-level alternating current voltage source indicate that the surface tends to impair the discharge uniformity and stimulate complementary filamentation. Upon analyzing the detailed transient processes, it is found that the alternations of filament positions in positive and negative discharges are mainly attributed to the local residual electrons and the electric field distortion near the wavy surface.

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Numerical simulation of the effect of water admixtures on the evolution of a helium/dry air discharge

Cited by 19 publications

References 103 publications

Influence of Oxygen on the Multiple-Current-Pulse Behavior in an Atmospheric Homogeneous Helium Dielectric Barrier Discharge With Air Impurities

Influence of Oxygen on the Multiple-Current-Pulse Behavior in an Atmospheric Homogeneous Helium Dielectric Barrier Discharge With Air Impurities

A Practical Method for Controlling the Asymmetric Mode of Atmospheric Dielectric Barrier Discharges

How does the moderate wavy surface affect the discharge behavior in an atmospheric helium dielectric barrier discharge model?

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