Density and temperature measurement of OH radicals in atmospheric-pressure pulsed corona discharge in humid air

Nakagawa, Yusuke; Ono, Ryo; Oda, Tetsuji

doi:10.1063/1.3638457

Cited by 71 publications

(45 citation statements)

References 25 publications

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“…In Ref. 28, the density of OH generated by ozone photodissociation was estimated to be approximately 1 Â 10 13 cm À3 under the following conditions: O 3 density was 1000 ppm, H 2 O density was 2.3%, and energy density of the laser beam was 2.5 mJ/cm 2 , these were similar conditions to those in the present experiment. This density was 1% of the estimated density of OH generated by the surface-DBD.…”

Section: Local Density Of Oh In the Surface Streamersupporting

confidence: 82%

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Measurement of OH (X2Σ) in immediate vicinity of dielectric surface under pulsed dielectric barrier discharge at atmospheric pressure using two geometries of laser-induced fluorescence

Teramoto

Kim

Ogata

et al. 2014

Journal of Applied Physics

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The behavior of the ground state OH radical was studied in humid air using pulsed surface dielectric barrier discharge. The validity of OH measurement in immediate vicinity of the dielectric surface was discussed using two geometries of laser-induced fluorescence (LIF) measurement, and surface distribution and temporal profiles of OH were examined. A comparison of parallel- and perpendicular-LIF techniques for OH measurement revealed that OH was mostly produced in a region several tens of μm above the dielectric surface. The surface distribution profile of OH agreed well with that of N2(C), and in both cases, the total production generated by a discharge pulse was proportional to the discharge energy. The OH local density in surface streamer channels was estimated to be 1.3 × 1015 cm−3 according to the decay rate of OH, which was similar to that in corona discharge. Additionally, the local density of OH remained constant regardless of discharge energies. These results indicate that the yield of OH increased with the discharge energy owing to expansion of the surface streamer region, increase in streamer radius or thickness or the number of branches, whereas the local density of OH in the streamer channel remained constant regardless of discharge energy.

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Section: Local Density Of Oh In the Surface Streamersupporting

confidence: 82%

“…This estimated density was less than or similar to that measured in pulsed corona discharge in humid air (1-2 Â 10 15 cm À3 ). 28 The triangles in Fig. 13 show calibrated [OH] ave with the assumption of the temperature change described above considering a(T).…”

Section: Local Density Of Oh In the Surface Streamermentioning

confidence: 99%

Measurement of OH (X2Σ) in immediate vicinity of dielectric surface under pulsed dielectric barrier discharge at atmospheric pressure using two geometries of laser-induced fluorescence

Teramoto

Kim

Ogata

et al. 2014

Journal of Applied Physics

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“…For further understanding of the products in the plasma-treated water, measurements of the densities of active species such as H and OH radicals are expected using laser-induced fluorescence spectroscopic methods. [29][30][31][32] In such future works, TDLAS will be a useful tool for acquiring basic data on water molecule density in the plasma reaction zone.…”

Section: Discussionmentioning

confidence: 99%

Measurements of water molecule density by tunable diode laser absorption spectroscopy in dielectric barrier discharges with gas–water interface

Tachibana

Nakamura

Kawasaki

et al. 2017

Jpn. J. Appl. Phys.

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We measured water molecule (H 2 O) density by tunable diode-laser absorption spectroscopy (TDLAS) for applications in dielectric barrier discharges (DBDs) with a gas-water interface. First, the effects of water temperature and presence of gas flow were tested using a Petri dish filled with water and a gas injection nozzle. Second, the TDLAS system was applied to the measurements of H 2 O density in two types of DBDs; one was a normal (non-inverted) type with a dielectric-covered electrode above a water-filled counter electrode and the other was an inverted type with a water-suspending mesh electrode above a dielectric-covered counter electrode. The H 2 O density in the normal DBD was close to the density estimated from the saturated vapor pressure, whereas the density in the inverted DBD was about half of that in the former type. The difference is attributed to the upward gas flow in the latter type, that pushes the water molecules up towards the gas-water interface.

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“…An optical parametric oscillator (OPO) is used to excite OH radicals in the X 2 Π(v = 0) ground state to the A 2 Σ(v = 1) excited state by 282-nm transition [7]- [10] (see Fig. 1).…”

Section: A Lifmentioning

confidence: 99%

Investigation of Humidity Effect on Atmospheric Plasma Decomposition of Toxic Gas With Direct Optical Measurement of OH Radicals

Nakagawa

Ono

Oda

2014

IEEE Trans. on Ind. Applicat.

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Plasma application for environment improvement is desirable. In order to improve the efficiency of toxic gas decomposition by plasma, it is worthwhile to clarify the behavior of radicals in nonthermal plasma. Although previous studies have revealed the behavior of radical densities and temperatures in atmospheric discharge, they are not yet connected to apprehension or simulation of practical toxic gas decomposition by atmospheric plasma. In this study, the coaxial dielectric barrier discharge cylinder reactor is prepared, where the radical behavior and the toxic gas decomposition efficiency can be measured altogether. The density of OH radical is directly measured by laser-induced fluorescence, and trichloroethylene (TCE) decomposition efficiency is also investigated in the same reactor. TCE decomposition efficiency is suppressed as background humidity increases. On another front, OH density measurement in ac barrier discharge indicates that OH density is about 2-4 ×10 11 cm −3 in time and spatial average and saturated with increasing humidity. From the saturation pattern, the initial OH density is estimated to be about the order of 10 14 cm −3 in streamer site. In addition, TCE addition in background reduces OH density, which indicates that OH reacts with TCE. The reason for the suppression of decomposition efficiency with increasing humidity is estimated as a consequence of O radical reduction by water-originated particles.Index Terms-Atmospheric plasma, dielectric barrier discharge (DBD), laser-induced fluorescence (LIF), OH radical, pollution control.

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Density and temperature measurement of OH radicals in atmospheric-pressure pulsed corona discharge in humid air

Cited by 71 publications

References 25 publications

Measurement of OH (X2Σ) in immediate vicinity of dielectric surface under pulsed dielectric barrier discharge at atmospheric pressure using two geometries of laser-induced fluorescence

Measurement of OH (X2Σ) in immediate vicinity of dielectric surface under pulsed dielectric barrier discharge at atmospheric pressure using two geometries of laser-induced fluorescence

Measurements of water molecule density by tunable diode laser absorption spectroscopy in dielectric barrier discharges with gas–water interface

Investigation of Humidity Effect on Atmospheric Plasma Decomposition of Toxic Gas With Direct Optical Measurement of OH Radicals

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