Discharge effects on gas flow dynamics in a plasma jet

Xian, Y.; Qaisrani, M. Hasnain; Yue, Yuanfu; Lü, Xin

doi:10.1063/1.4964784

Cited by 44 publications

(37 citation statements)

References 30 publications

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“…A jet emerging in open space, however, even if it starts being laminar, will turn into a turbulent jet far enough downstream. For typical operating conditions of APPJs, the laminar-to-turbulent transition occurs ~2 cm from the nozzle (this distance depends on gas flow rate) [28]. Since the gap between the nozzle and the substrate is only 0.5 cm in the present work, we can safely assume that the jet remains laminar.…”

Section: Model Descriptionmentioning

confidence: 93%

Gas flow rate dependence of the discharge characteristics of a helium atmospheric pressure plasma jet interacting with a substrate

Yan

Economou

2017

J. Phys. D: Appl. Phys.

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A 2D (axisymmetric) computational study of the discharge characteristics of an atmospheric pressure plasma jet as a function of gas flow rate was performed. The helium jet emerged from a dielectric tube, with an average gas flow velocity in the range 2.5-20 m s −1 (1 atm, 300 K) in a nitrogen ambient, and impinged on a substrate a short distance dowstream. The effect of the substrate conductivity (conductror versus insulator) was also studied. Whenever possible, simulation predictions were compared with published experimental observations. Discharge ignition and propagation in the dielectric tube were hardly affected by the He gas flow velocity. Most properties of the plasma jet, however, depended sensitively on the He gas flow velocity, which determined the concentration distributions of helium and nitrogen in the mixing layer forming in the gap between the tube exit and the substrate. At low gas flow velocity, the plasma jet evolved from a hollow (donut-shaped) feature to one where the maximum of electron density was on axis. When the gas flow velocity was high, the plasma jet maintained its hollow structure until it struck the substrate. For a conductive substrate, the radial ion fluxes to the surface were relatively uniform over a radius of ~0.4-0.8 mm, and the dominant ion flux was that of He +. For a dielectric substrate, the radial ion fluxes to the surface peaked on the symmetry axis at low He gas flow velocity, but a hollow ion flux distribution was observed at high gas flow velocity. At the same time, the main ion flux switched from N + 2 to He + 2 as the He gas flow velocity increased from a low to a high value. The diameter of the plasma 'footprint' on the substrate first increased with increasing He gas flow velocity, and eventually saturated with further increases in velocity.

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Section: Model Descriptionmentioning

confidence: 93%

Gas flow rate dependence of the discharge characteristics of a helium atmospheric pressure plasma jet interacting with a substrate

Yan

Economou

2017

J. Phys. D: Appl. Phys.

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“…It is observed that when only the central jet tube is ignited, the plasma plume propagates straight as the results of single plasma jets. [22,32,33] With the three jet tubes ignited in the jet arrays, the two outside plumes show divergence in the propagation trajectory, especially from He jet array.…”

Section: Methodsmentioning

confidence: 99%

“…[3] This result is consistent with the results of the single plasma jets. [33,35] The transition will be further studied in section 3.3 using the Schlieren photographs. From Figure 6(a) and (b), it can be seen that the central plume propagation depends largely on the flow rate rather than the applied voltage in our jet array configuration and experimental conditions.…”

Section: Effects Of Flow Rate and Applied Voltage On The Plume Charmentioning

confidence: 99%

Jet‐to‐jet interactions in atmospheric‐pressure plasma jet arrays for surface processing

Liu

Zhang

Fang

et al. 2017

Plasma Processes & Polymers

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Atmospheric Pressure Plasma Jet (APPJ) arrays are considered as one of the most promising methods for uniform plasma processing of large uneven surfaces. To improve the downstream uniformity and enhance the surface treatment effects, it is important to reveal the mechanisms of the jet‐to‐jet interactions of plasma plumes in the jet array. In this paper, the electrical, optical, and fluid characteristics of the He and Ar three‐channel one‐dimensional (1D) plasma jet arrays with cross‐field needle‐ring electrode structure are studied and compared. It is found that there are divergences in the outside plumes of the propagation trajectory by the repellency of the plasma bullets and the spatial uniformity of the He and Ar plasma jet arrays can be improved with a lower applied voltage and a higher gas flow rate. The deflection angle of side plumes with respect to the central one of He is larger than that of Ar jet array due to the lighter molecular weight and better discharge synchronization. The experimental results show that Ar jet array is more controllable and stable and is more suitable for the design of the practical, simpler, and cheaper scalable plasma jet arrays.

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“…We were able to point in this way that, for constant flow rate conditions and fixed electrode arrangement, the length of the outside jet depends on the frequency and amplitude of the driving high voltage pulses ( Figure 6). Supplementary, it has been demonstrated in a number of recent studies, that this characteristic dimension of the outside plasma jets in helium is also influenced by the electrodes dimensions and constructive details [40,41], gas flow rate [38,[42][43][44], dielectric tube diameter [45][46][47].…”

Section: Plasma Source Quasi-stationary Working Regimementioning

confidence: 99%

Time Behaviour of Helium Atmospheric Pressure Plasma Jet Electrical and Optical Parameters

et al. 2017

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Low temperature plasma jets gained increased interest in the last years as a potential device in many life science applications, including here human or veterinary medicine. Standardisation of plasma sources and biological protocols are necessary for quality assurance reasons, due to the fact that this type of atmospheric pressure plasma source is available in multiple configurations and their operational parameters span also on a broad range of items, such as all characteristics of high voltage pulses used for gas breakdown, geometrical characteristics, gas feed composition and conductive or biological target characteristics. In this paper we present results related to electrical, optical and molecular beam mass spectrometry diagnosis of a helium plasma jet, emphasising the influence of various operational parameters of the high voltage pulses on plasma jet properties. Discussion on physical parameters that influence the biological response is included, together with important results on plasma sources statistical behaviour until reaching a quasi-stationary working regime. The warm-up period of the plasma jet, specific to many other plasma sources, must be precisely known and specified whenever the plasma jets are used as a tool for life science applications.

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Discharge effects on gas flow dynamics in a plasma jet

Cited by 44 publications

References 30 publications

Gas flow rate dependence of the discharge characteristics of a helium atmospheric pressure plasma jet interacting with a substrate

Gas flow rate dependence of the discharge characteristics of a helium atmospheric pressure plasma jet interacting with a substrate

Jet‐to‐jet interactions in atmospheric‐pressure plasma jet arrays for surface processing

Time Behaviour of Helium Atmospheric Pressure Plasma Jet Electrical and Optical Parameters

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