Plasma chemistry model of surface microdischarge in humid air and dynamics of reactive neutral species

Sakiyama, Yukinori; Graves, David B.; Chang, Hung‐Wen; Shimizu, Tetsuji; Morfill, G. E.

doi:10.1088/0022-3727/45/42/425201

Cited by 432 publications

(442 citation statements)

References 34 publications

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“…Mathematical models simulating the chemical yield of reactive species from a surface DBD plasma sometimes do not take into account the convective mechanisms [52][53][54][55], but this work shows how important they can actually be. The convective mechanism induced by the air jet is also generating a region with a negative pressure gradient above the exposed electrode.…”

Section: Discussionmentioning

confidence: 99%

Geometry optimization of linear and annular plasma synthetic jet actuators

Neretti¹,

Seri²,

Taglioli³

et al. 2016

J. Phys. D: Appl. Phys.

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The Electro-Hydro-Dynamic (EHD) interaction induced in atmospheric-pressure air by a surface Dielectric Barrier Discharge (DBD) actuator has been experimentally investigated. Plasma Synthetic Jets Actuators (PSJAs) are DBD actuators able to induce an air stream, perpendicular to the actuator surface. These devices can be used in the aerodynamics field to prevent or induce flow separation, modify the laminar to turbulent transition inside the boundary layer, and stabilize or mix air flows. They can also be used to enhance indirect plasma treatment effects, increasing the reactive species delivery rate onto surfaces and liquids. This can play a major role in plasma processing and chemical kinetics modelling, where only diffusive mechanisms are often considered. This paper reports on the importance that different electrode geometries can have on the performance of different PSJAs. A series of DBD aerodynamic actuators designed to produce perpendicular jets have been fabricated on 2-layer printed circuit boards (PCBs). Linear and annular geometries have been considered, testing different upper electrode distances in the linear case and different diameters in the annular one. AC voltage supplied at 11.5 kV peak and 5 kHz frequency has been used. Lower electrodes were connected to ground and buried in epoxy resin to avoid undesired plasma generation on the lower actuator surface.Voltage and current measurements have been carried out to evaluate the active power delivered to the discharges. Schlieren imaging allowed to visualize the induced jets and gave an estimate of their evolution and geometry. Pitot tube measurements were performed to obtain the PSJAs' velocity profiles and to estimate the mechanical power delivered to the fluid.Optimal values of the inter-electrode distance and diameter have been found in order to maximize jet velocity, mechanical power or efficiency. Annular geometries are found to achieve the best performances.

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Section: Discussionmentioning

confidence: 99%

Geometry optimization of linear and annular plasma synthetic jet actuators

Neretti¹,

Seri²,

Taglioli³

et al. 2016

J. Phys. D: Appl. Phys.

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“…Such models may involve dozens of chemical species and thousands of reactions [117,41,95]. Each reaction is characterized by a rate constant, and these are are never known with certainty.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty and error in complex plasma chemistry models

Turner

2015

Plasma Sources Sci. Technol.

101

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Abstract. Chemistry models that include dozens of species and hundreds to thousands of reactions are common in low-temperature plasma physics. The rate constants used in such models are uncertain, because they are obtained from some combination of experiments and approximate theories. Since the predictions of these models are a function of the rate constants, these predictions must also be uncertain. However, systematic investigations of the influence of uncertain rate constants on model predictions are rare to non-existent. In this work we examine a particular chemistry model, for helium-oxygen plasmas. This chemistry is of topical interest because of its relevance to biomedical applications of atmospheric pressure plasmas. We trace the primary sources for every rate constant in the model, and hence associate an error bar (or equivalently, an uncertainty) with each. We then use a Monte Carlo procedure to quantify the uncertainty in predicted plasma species densities caused by the uncertainty in the rate constants. Under the conditions investigated, the range of uncertainty in most species densities is a factor of two to five. However, the uncertainty can vary strongly for different species, over time, and with other plasma conditions. There are extreme (pathological) cases where the uncertainty is more than a factor of ten. One should therefore be cautious in drawing any conclusion from plasma chemistry modelling, without first ensuring that the conclusion in question survives an examination of the related uncertainty. PACS numbers:Uncertainty and Error in Complex Plasma Chemistry Models 2

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“…Because the atmospheric pressure discharges contain multiple impurities that interact with the carrier gas during operation in the plasma chamber. The functionality of DBD plasma has been modified by the existence of humidity in the air [17,18], hence we incorporate as a trace impurity of the water vapour for the realistic modelling of atmospheric pressure discharges in He-air gas mixture. It has been observed from the experimental measurements [20,21] that the Penning ionization provided a significant amount of ionization in He-N 2 DBD plasma at atmospheric pressure.…”

Section: Introductionmentioning

confidence: 99%

Influence of Gap Spacing between Dielectric Barriers in Atmospheric Pressure Discharges

Iqbal

Turner

2015

Contrib. Plasma Phys.

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The breakdown activity in helium atmospheric pressure dielectric barrier discharge (DBD) plasma is strongly modified by introducing small impurities (nitrogen (N2) and air in ppm), although its precise implications for the behavior of discharge plasma is not evident under several constraints. In this simulation study, we investigate the influence of gap spacing between the dielectric barriers to explore the dynamic modification in the structure of discharge plasma in distinct phases of the discharge current pulse using a two-dimensional fluid model in He-air gas mixture. Specifically, the impact of nitrogen and air impurities is contrasted by exploring the spatial distributions of electrons in the breakdown phase under similar operating conditions. The filamentary mode of DBD plasma in He-N2 is transformed into uniform glow discharge in He-air gas mixture by the dominant effect of Penning ionization. Finally, the outcomes of two-dimensional fluid model are validated by comparing with three-dimensional fluid model to provide the reliability of numerical simulations.

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Plasma chemistry model of surface microdischarge in humid air and dynamics of reactive neutral species

Cited by 432 publications

References 34 publications

Geometry optimization of linear and annular plasma synthetic jet actuators

Geometry optimization of linear and annular plasma synthetic jet actuators

Uncertainty and error in complex plasma chemistry models

Influence of Gap Spacing between Dielectric Barriers in Atmospheric Pressure Discharges

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