Interpretation of the gas flow field modification induced by guided streamer (‘plasma bullet’) propagation

Papadopoulos, Polycarpos K.; Vafeas, Panayiotis; Svarnas, P.; Gazeli, Kristaq; Hatzikonstantinou, P.; Gkelios, A.; Clément, Franck

doi:10.1088/0022-3727/47/42/425203

Cited by 77 publications

(69 citation statements)

References 19 publications

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“…The developing turbulent flow fields observed in Fig. 1(b–d) are entirely consistent with all others in the literature10111213; the turbulent flow fields generated downstream of atmospheric plasma plumes have been qualitatively observed over a wide range of Reynolds number (135–840), applied voltage (8–30 kV peak-peak) and frequencies (125–50,000 Hz; St θ = fθ / U m = 0.000012–0.035, where θ (~0.01 D ) is the momentum thickness of the shear layers at the jet exit).…”

Section: Resultssupporting

confidence: 90%

Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device

Whalley

Walsh

2016

Sci Rep

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Flowing low temperature atmospheric pressure plasma devices have been used in many technological applications ranging from energy efficient combustion through to wound healing and cancer therapy. The generation of the plasma causes a sudden onset of turbulence in the inhomogeneous axisymmetric jet flow downstream of the plasma plume. The mean turbulent velocity fields are shown to be self-similar and independent of the applied voltage used to generate the plasma. It is proposed that the production of turbulence is related to a combination of the small-amplitude plasma induced body forces and gas heating causing perturbations in the unstable shear layers at the jet exit which grow as they move downstream, creating turbulence.

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Section: Resultssupporting

confidence: 90%

Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device

Whalley

Walsh

2016

Sci Rep

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“…Using the measured Tgas from Figure 13 and the electron density of the plasma, the ionization degree can be estimated under our experimental conditions, as it is shown below. Concerning the electron density of GIWs that were generated with the present device, an approximation was made by our group using a modified version of the related DBD reactor (i.e., single-electrode linear-field geometry) [32]. The device was operated in pure helium at 2 slm and driven with sinusoidal high voltage (20 kV p-p, 10 kHz).…”

Section: Optical Emission Characteristics Of Giwsmentioning

confidence: 99%

“…Although, the electrodes that are used therein are in the form of very thin rings, which are entirely enclosed in the dielectric material, thus avoiding any contact with the atmospheric air for better insulation. Besides, setups using one single electrode have been also proposed [19,[32][33][34][35][36], which in some cases, are directly compared with linear-field configurations in the same study [28]. In most of these setups, quartz is used as dielectric material and helium as the process gas, which are quite reliable.…”

Section: Introductionmentioning

confidence: 99%

“…A compact low-cost DBD reactor of very simple geometry is used for the production of GIWs. It uses alumina as a dielectric, it is designed to operate both with µs-pulsed (demonstrated herein) and sinusoidal HV [32], and it can be employed both for fundamental studies (experimental/numerical, see [32] for instance) and microplasma-based applications. The temporal variation of the dielectric tube temperature is thoroughly investigated versus the electrical parameters of a positive µs-pulsed power supply.…”

Section: Introductionmentioning

confidence: 99%

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Electrical, Thermal and Optical Parametric Study of Guided Ionization Waves Produced with a Compact μs-Pulsed DBD-Based Reactor

Doanh

Held

Clément

2017

Plasma

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Atmospheric pressure guided ionization waves (GIWs) that are driven by ns/µs-pulsed high voltages, are promising tools in the biomedical field allowing for the effective production of reactive species and metastables without thermal damages of the specimens that are exposed. In most cases, plasma is produced in noble gases using dielectric barrier discharge (DBD) devices of more-or-less sophisticated geometries. In this study, a compact low-cost DBD reactor of very simple geometry is presented. It is fed with pure helium and driven by positive µs-pulsed high voltage (amplitude: 4.5-8 kV, pulse width: 1-10 µs) of audio frequencies (5-20 kHz), while it operates consistently for long time periods in a wide range of conditions. The produced plasma exhibits propagation lengths up to 4 cm and rich chemical reactivity is established outside the reactor, depending on the device's experimental parameters. Besides, the dielectric tube's temperature during plasma operation is an important factor, which is linked to the plasma characteristics. This temperature and its variations are thoroughly investigated herein, along with GIWs electrical features versus the electrical parameters of the pulsed power supply. Accordingly, it is demonstrated that not all of the operational windows are adequate for thermal-free operation and suitable operating conditions of this system are proposed for diverse applications, such as biomedical (low gas temperature is a prerequisite) and surface treatments of solid materials (low temperatures are not required).

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“…1,13 Helium plasma jet and Neon plasma plume under effect of atmospheric-pressure guided streamers were explained before. 14,15 The mechanism of plasma bullets traveling at high speed under high electric field has been explained by several groups. 17,19,20 Moreover the effects of high voltage waveform, pulse raise time, frequency, gas flow rate and tube material have been studied.…”

Section: Introductionmentioning

confidence: 99%

The density and velocity of plasma bullets propagating along one dielectric tube

Xia

et al. 2015

AIP Advances

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This study shows that the propagation of plasma bullets along one dielectric tube is strongly affected by many discharge parameters, such as the waveform of applied voltage (AC or pulsed DC), peak voltage, He flow rate, and the frequency of AC voltage. Analysis indicates that the density and velocity of plasma bullets are mainly determined by the electric field at the front of plasma bullets. These discharge parameters may significantly influence the distribution of plasma potential along the tube, thus control the electric field at the front of plasma bullets and their propagation. An increase in the pulsed DC voltage with its rise time of <40-50 ns can lead to an obvious improvement in the electric field at the front of plasma bullets, resulting in generation of a plasma in the high density gas and a fast propagation of plasma bullets. He flowing through the tube can contribute to the surface diffusion of charged species, and greatly increase the electric field at the front of plasma bullets. During the propagation of plasma bullets, their density is decreased due to the surface recombination of charged species, such as electrons and ions.

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Interpretation of the gas flow field modification induced by guided streamer (‘plasma bullet’) propagation

Cited by 77 publications

References 19 publications

Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device

Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device

Electrical, Thermal and Optical Parametric Study of Guided Ionization Waves Produced with a Compact μs-Pulsed DBD-Based Reactor

The density and velocity of plasma bullets propagating along one dielectric tube

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