Investigation of water dissociation by Nanosecond Repetitively Pulsed Discharges in superheated steam at atmospheric pressure

Sainct, Florent P.; Lacoste, Déanna A.; Laux, Christophe O.; Kirkpatrick, Mike; Odic, Emmanuel

doi:10.2514/6.2013-1190

Cited by 8 publications

(4 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The use of this diagnostics in plasmas with significant amounts of water vapor is simplified considerably by the fact that pure rotational Raman spectrum of water vapor is very weak, about 5 orders of magnitude weaker compared to that of nitrogen [12]. This, as well as straightforward absolute calibration using pure rotational Raman spectra, makes the present approach an attractive alternative to ns pulse discharge electron density inference from optical emission spectra, based on Stark broadening of atomic emission lines [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Electron density and electron temperature measurements in nanosecond pulse discharges over liquid water surface

Simeni

Roettgen

Petrishchev

et al. 2016

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

Time-resolved electron density, electron temperature, and gas temperature in nanosecond pulse discharges in helium and O 2-He mixtures near liquid water surface are measured using Thomson/pure rotational Raman scattering, in two different geometries, (a) 'diffuse filament' discharge between a spherical high-voltage electrode and a grounded pin electrode placed in a reservoir filled with distilled water, with the tip exposed, and (b) dielectric barrier discharge between the high-voltage electrode and the liquid water surface. A diffuse plasma filament generated between the electrodes in helium during the primary discharge pulse exhibits noticeable constriction during the secondary discharge pulse several hundred ns later. Adding oxygen to the mixture reduces the plasma filament diameter and enhances constriction during the secondary pulse. In the dielectric barrier discharge, diffuse volumetric plasma occupies nearly the entire space between the high voltage electrode and the liquid surface, and extends radially along the surface. In the filament discharge in helium, adding water to the container results in considerable reduction of plasma lifetime compared to the discharge in dry helium, by about an order of magnitude, indicating rapid electron recombination with water cluster ions. Peak electron density during the pulse is also reduced, by about a factor of two, likely due to dissociative attachment to water vapor during the discharge pulse. These trends become more pronounced as oxygen is added to the mixture, which increases net rate of dissociative attachment. Gas temperature during the primary discharge pulse remains near room temperature, after which it increases up to T ~ 500 K over 5 µs and decays back to near room temperature before the next discharge pulse several tens of ms later. As expected, electron density and electron temperature in diffuse DBD plasmas are considerably lower compared to peak values in the filament discharge. Use of Thomson scattering for measurements of electron density and electron temperature in near-surface plasmas is hindered by strong light scattering off the surface.

show abstract

Section: Introductionmentioning

confidence: 99%

Electron density and electron temperature measurements in nanosecond pulse discharges over liquid water surface

Simeni

Roettgen

Petrishchev

et al. 2016

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Previous investigations of NRP plasmas have used multiple diagnostic techniques including optical emission spectroscopy (OES), Stark broadening, laser Thomson/Rayleigh scattering, laser induced fluorescence (LIF), microwave Rayleigh scattering, electrical measurements (voltage, current, resistance of the plasma column), etc. [19][20][21][22][23][24][25][26] A comprehensive study of the single-pulse ns-discharge is still lacking and would provide valuable insight for interpreting the physics of NRP discharges.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of atmospheric pressure single-pulse nanosecond discharge in pin-to-pin configuration

Wang

Patel

Bane

et al. 2021

Journal of Applied Physics

View full text Add to dashboard Cite

We present an experimental study of nanosecond high-voltage discharges in a pin-to-pin electrode configuration at atmospheric conditions operating in single-pulse mode (no memory effects). Discharge parameters were measured using microwave Rayleigh scattering, laser Rayleigh scattering, optical emission spectroscopy enhanced with a nanosecond probing pulse, and fast photography. Spark and corona discharge regimes were studied for electrode gap sizes 2-10 mm and discharge pulse duration of 90 ns. The spark regime was observed for gaps < 6 mm using discharge pulse energies of 0.6-1 mJ per mm of the gap length. Higher electron number densities, total electron number per gap length, discharge currents, and gas temperatures were observed for smaller electrode gaps and larger pulse energies, reaching maximal values of about 7.510 15 cm -3 , 3.510 11 electrons per mm, 22 A, and 4,000 K (at 10 s after the discharge), respectively, for a 2 mm gap and 1 mJ/mm discharge pulse energy. Initial breakdown was followed by a secondary breakdown occurring about 30-70 ns later and was associated with ignition of a cathode spot and transition to cathodic arc. A majority of the discharge pulse energy was deposited into the gas before the secondary breakdown (85-89%). The electron number density after the ns-discharge pulse decayed with a characteristic time scale of 150 ns governed by dissociative recombination and electron attachment to oxygen mechanisms. For the corona regime, substantially lower pulse energies (~0.1 mJ/mm), peak conduction current (1-2 A), and electron numbers (3-510 10 electrons per mm), and gas temperatures (360 K) were observed.

show abstract

“…High-resolution measurements of the temporal evolution of NRP plasmas are critical for understanding the discharge physics and ultimately for designing plasma sources tailored to specific applications. Conventional diagnostics of NRP discharges include optical emission spectroscopy (OES), Stark broadening, fast photography, measurements of voltage and current waveforms, etc [19][20][21][22][23]. One of the most important characteristics of NRP plasmas is electron number density.…”

mentioning

confidence: 99%

“…Another method for measuring electron density from OES spectra is to use Stark broadening of the atomic nitrogen line and H α /H β . This method was used to measure electron density of NRP plasmas in various kinds of gas mixtures, with resulting electron density in the range of 10 15 -10 18 cm −3 [22,23]. One potential issue, however, is that Stark broadening sensitivity is limited for electron densities >10 15 cm −3 [23].…”

mentioning

confidence: 99%

Time-resolved measurements of electron density in nanosecond pulsed plasmas using microwave scattering

Wang¹,

Stockett²,

Jagannath³

et al. 2018

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

In this work, Rayleigh microwave scattering was utilized to measure the electron number density produced by nanosecond high voltage breakdown in air between two electrodes in a pin-to-pin configuration (peak voltage 26 kV and pulse duration 55 ns). The peak electron density decreased from 1•10 17 cm -3 down to 7•10 14 cm -3 when increasing the gap distance from 2 to 8 mm (total electron number decreased from 2•10 13 down to 5•10 11 respectively). Electron number density decayed on the timescale of about several s due to dissociative recombination.

show abstract

Investigation of water dissociation by Nanosecond Repetitively Pulsed Discharges in superheated steam at atmospheric pressure

Abstract: International audienc

Cited by 8 publications

References 14 publications

Electron density and electron temperature measurements in nanosecond pulse discharges over liquid water surface

Electron density and electron temperature measurements in nanosecond pulse discharges over liquid water surface

Experimental study of atmospheric pressure single-pulse nanosecond discharge in pin-to-pin configuration

Time-resolved measurements of electron density in nanosecond pulsed plasmas using microwave scattering

Contact Info

Product

Resources

About