Temporal evolution of temperature and OH density produced by nanosecond repetitively pulsed discharges in water vapour at atmospheric pressure

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

doi:10.1088/0022-3727/47/7/075204

Cited by 13 publications

(12 citation statements)

References 19 publications

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“…The He-H 2 O chemical kinetics set reported by Liu et al [22] has been used to model a capacitively coupled RF discharge; and the predicted OH and H 2 O 2 densities in the model showed good agreement with the experimentally measured values [28]. The kinetics of pure water discharges have not been extensively studied by either experiments or modeling, with few exceptions [29,30].…”

Section: Introductionmentioning

confidence: 88%

“…Discharges in pure water vapor often occur in direct liquid discharges or discharges generated in bubbles [1]. The kinetics of pure water discharges have not been extensively investigated by either experiments or modeling with few exceptions [29,30]. As absolute LIF measurements of OH and H in pure water discharges are challenging due to the high collisional quenching rate of water with the excited states of OH and H [44,55], we only computationally investigated these discharges.…”

Section: Comparison Of Low Energy Ar − 1% H 2 O With Pure Water Disch...mentioning

confidence: 99%

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Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H₂O and H₂O

Luo

Lietz

Yatom

et al. 2018

J. Phys. D: Appl. Phys.

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The plasma kinetics of Ar-H 2 O and H 2 O at atmospheric pressure are of interest for applications in biotechnology where rare-gas plasma jets treat liquid surfaces and in water treatment where discharges are generated in bubbles or directly in liquid water. Due to evaporation resulting from heat transfer to the liquid, for many conditions the mole fraction of water in the plasma can be large-approaching nearly pure water. In this paper, results are discussed from a combined experimental and computational investigation of the chemical kinetics in a high electron density plasma filament sustained in Ar-H 2 O at atmospheric pressure. The chemical kinetics were simulated using a 0D global model, validated by measurements of the absolute OH and H densities by laser induced fluorescence (LIF) and two-photon absorption LIF. The primary sources of H and OH during the discharge pulse are dissociative excitation transfer from metastable Ar atoms and Ar dimer excimers at low water concentration and electron impact dissociation of H 2 O at high water concentration. In spite of their similar sources, the density of OH was measured to be two orders of magnitude smaller than that of H at power densities on the order of 10 5 Jm −3 . This disparity is due to electron impact dissociation of OH during the discharge pulse and rapid reactions of OH in the presence of high H and O densities in the afterglow. It is often assumed that OH is the dominant non-selective reactive species in water-containing plasmas. These results reinforce the importance of atomic species such as H and O in water containing high energy density plasmas. A numerical parametric study revealed that the lowest energy cost for H 2 O 2 production is achieved at low energy densities in pure water. The high concentration of atomic radicals, which rapidly recombine, results in an overall lower energy efficiency of reactive species production. In particular, the selectivity of H 2 O 2 production decreases with increasing power density which instead favors H 2 and O 2 production.

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Section: Introductionmentioning

confidence: 88%

Section: Comparison Of Low Energy Ar − 1% H 2 O With Pure Water Disch...mentioning

confidence: 99%

Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H₂O and H₂O

Luo

Lietz

Yatom

et al. 2018

J. Phys. D: Appl. Phys.

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“…The voltage and current of the discharge can be measured by attaching probes directly on the high voltage electrodes. This direct configuration was used in previous work at the EM2C laboratory and gave satisfactory results [11,21,24,65,66]. However, the probes occupy a significant volume around the discharge, which is not always compatible with optical diagnostics.…”

Section: Appendix: Effect Of Probe Location On Voltage and Current Tr...mentioning

confidence: 97%

Plasma-assisted combustion with nanosecond discharges. I: Discharge effects characterization in the burnt gases of a lean flame

Minesi

Blanchard

Pannier

et al. 2022

Plasma Sources Sci. Technol.

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The prediction of a flame response to plasma assistance requires extensive knowledge of discharge-induced plasma kinetics. Detailed studies of nanosecond discharges are common in N2/O2 and fresh combustible mixtures but are still lacking in burnt gases. To fill this gap, we define a combustion reference test case and investigate the effects of Nanosecond Repetitively Pulsed (NRP) discharges placed in the recirculation zone of a lean (Φ = 0.8) CH4-air bluff-body stabilized flame at atmospheric pressure. In this zone, the plasma discharge is created in a mixture of burnt gases. Quantitative Optical Emission Spectroscopy (OES), coupled with measurements of electrical energy deposition, is performed to provide temporally (2 ns) and spatially (0.5 mm) resolved evolutions of the temperatures and concentrations of N2(B), N2(C), N2 +(B), OH(A), NH(A), and CN(B) in the discharge. At steady state, the 10-ns pulses deposit 1.8 mJ at a repetition frequency of 20 kHz. Spatially resolved temperature profiles are measured during the discharge along the interelectrode gap. The temperature variations are more pronounced near the electrodes than in the middle of the gap. On average, the gas temperature increases by approximately 550 K. The heat release corresponds to about 20% of the total deposited electric energy. The electron number density, measured by Stark broadening of Hα, increases up to about 1016 cm-3. These characteristics allow to classify the discharge as a non-equilibrium NRP spark, as opposed to the thermal NRP spark where the temperature can reach 40,000 K and the degree of ionization is close to 100%. These measurements will serve (i) as a reference for future studies in the Mini-PAC burner at the same conditions, (ii) to test discharge kinetic models, and (iii) to derive a simplified model of plasma-assisted combustion, which will be presented in companion paper.

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“…Dilecce et al [21,27] studied OH radicals in He/H 2 O and Ar/H 2 O pulsed dielectric barrier discharges, and pointed out that water vapor content and gas composition might change the microscopic process of plasma chemistry, which in turn changes the spatial and temporal distribution of OH radicals. Sainct et al [28] reported the lifetime of OH radicals produced in a nanosecond pulsed water vapor discharge to be about 50 μs. Ono et al [29,30] investigated the decay behavior of OH radicals in a pulsed pin-plate corona discharge and measured the spatial and temporal distribution of OH density in a He/H 2 O atmospheric pressure jet by LIF and found that OH radicals were primarily produced by the recombination of H 2 O + rather than electron-impact dissociation of H 2 O.…”

Section: Introductionmentioning

confidence: 99%

The investigation of OH radicals produced in a DC glow discharge by laser-induced fluorescence spectrometry

Liu¹,

Zhuang²,

Chu³

et al. 2021

Plasma Sci. Technol.

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In this paper the OH radicals produced by a needle–plate negative DC discharge in water vapor, N2 + H2O mixture gas and He + H2O mixture gas are investigated by a laser-induced fluorescence (LIF) system. With a ballast resistor in the circuit, the discharge current is limited and the discharges remain in glow. The OH rotation temperature is obtained from fluorescence rotational branch fitting, and is about 350 K in pure water vapor. The effects of the discharge current and gas pressure on the production and quenching processes of OH radicals are investigated. The results show that in water vapor and He + H2O mixture gas the fluorescence intensity of OH stays nearly constant with increasing discharge current, and in N2 + H2O mixture gas the fluorescence intensity of OH increases with increasing discharge current. In water vapor and N2 + H2O mixture gas the fluorescence intensity of OH decreases with increasing gas pressure in the studied pressure range, and in He + H2O mixture gas the fluorescence intensity of OH shows a maximum value within the studied gas pressure range. The physicochemical reactions between electrons, radicals, ground and metastable molecules are discussed. The results in this work contribute to the optimization of plasma reactivity and the establishment of a molecule reaction dynamics model.

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Temporal evolution of temperature and OH density produced by nanosecond repetitively pulsed discharges in water vapour at atmospheric pressure

Cited by 13 publications

References 19 publications

Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H₂O and H₂O

Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H₂O and H₂O

Plasma-assisted combustion with nanosecond discharges. I: Discharge effects characterization in the burnt gases of a lean flame

The investigation of OH radicals produced in a DC glow discharge by laser-induced fluorescence spectrometry

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Temporal evolution of temperature and OH density produced by nanosecond repetitively pulsed discharges in water vapour at atmospheric pressure

Cited by 13 publications

References 19 publications

Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H2O and H2O

Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H2O and H2O

Plasma-assisted combustion with nanosecond discharges. I: Discharge effects characterization in the burnt gases of a lean flame

The investigation of OH radicals produced in a DC glow discharge by laser-induced fluorescence spectrometry

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Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H₂O and H₂O

Plasma kinetics in a nanosecond pulsed filamentary discharge sustained in Ar–H₂O and H₂O