Study of fast gas heating in a capillary nanosecond discharge in air. TALIF O atoms measurements and kinetic modeling.

Plasma Sources Sci. Technol.

Starikovskaia

2022

Fast gas heating in a pulsed nanosecond capillary discharge in pure CO2 under the conditions of high specific deposited energy (around 1.2 eV/molecule) and high reduced electric fields (150–250 Td) has been studied experimentally and numerically. Specific deposited energy, reduced electric field and gas temperature have been measured as functions of time. The radial distribution of the electron density has been analyzed experimentally. The role of quenching of O(1D), O(1S) and CO(a3Π) excited atoms and molecules leading to heat release at sub-microsecond time scale have been analyzed by numerical modeling in the framework of 1D axial approximation.

Section: Co 2 Dissociation In Nanosecond Discharges At High Specific ...mentioning

confidence: 88%

Fast gas heating and kinetics of electronically excited states in a nanosecond capillary discharge in CO₂

Pokrovskiy

Plasma Sources Sci. Technol.

Starikovskaia

2022

“…The correlation of the calculated gas temperature with experimental measurements was demonstrated in Ref. 15. The primary reactions leading to the production and losses of O atoms are in Table 1.…”

Section: B Description Of the 0d Detailed Kinetic Model: Discharge mentioning

confidence: 78%

“…Reactions (R8,R9) were for the first time proposed in Ref. 15 to explain the dynamics of a fast gas heating of N 2 :O 2 mixture at high degree of dissociation of molecular oxygen:…”

Section: D Kinetic Model Resultsmentioning

confidence: 99%

Experimental and numerical study of fast gas heating and O atom production in a capillary nanosecond discharge

Klochko

Salmon

52nd Aerospace Sciences Meeting

et al. 2014

Self Cite

A nanosecond repetitively pulsed discharge in a quartz capillary filled with flowing synthetic air was investigated as a benchmark to address the mechanism of fast gas heating for conditions of up to complete dissociation of O 2 and heating of a few thousand K occurring during the near afterglow phase. Electric current, electric field, gas temperature, energy deposition, and O atom concentrations were measured with respect to time. A 2-dimensional model was used to simulate discharge initiation and early breakdown, while a detailed 0D kinetic model was used to address the afterglow phase and fast gas heating. The high oxygen dissociation degree enables investigation of the key role played by O atoms in the fast gas heating chemistry.

“…were proposed in [30] to explain the dynamics of a fast gas heating of nitrogen-oxygen mixtures at high degree of O 2 molecules dissociation. Rate constants of these reactions were proposed using the analysis of the experimental data on N 2 (A 3  u  , v=7) quenching by atomic oxygen [46] and were taken to be k  7.510 -11 cm 3 /s.…”

Section: Model Descriptionmentioning

confidence: 99%

“…In the discharge, the measurements were carried out by fitting rotational structure of the 2 + nitrogen system, in the afterglow the data on gas temperature were obtained by using a series of reflected pulses with lower energy. The temporal evolution of O( 3 P) atoms density was presented in [30][31]. The measurements were carried out by the actinometry technique using the addition of argon atoms in N 2 : O 2 mixture and also by the TALIF method in the discharge afterglow.…”

Section: Introductionmentioning

confidence: 99%

Active Particles Production by Pulsed Nanosecond Discharge in Ambient Air. Quenching of Electronically Excited States of Nitrogen by O2 Molecules and O(3P) Atoms

53rd AIAA Aerospace Sciences Meeting

2015

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The results of a numerical study of kinetic processes initiated by pulsed nanosecond discharge in atmospheric-pressure air are presented. The calculations of temporal dynamics of electron concentration, density of atomic oxygen, vibrational distribution function of nitrogen molecules, and gas temperature agree with the experimental data. It was shown that quenching of electronically excited states of nitrogen N 2 (B 3 П g ), N 2 (С 3 П u ), N 2 (a' 1  u  ) by oxygen molecules leads to the dissociation of O 2 . This conclusion is based on the comparison of calculated dynamics of atomic oxygen in air, excited by pulsed nanosecond discharge, with experimental data.In air plasma at high dissociation degree of oxygen molecules, relaxation of electronic energy of atoms and molecules in reactions with O atoms becomes extremely important. Active production of NO molecules and fast gas heating in the discharge plasma due to the quenching of electronically excited N 2 (B 3 П g , C 3 П u , a' 1  u  ) molecules by oxygen atoms should be noted here. Owing to the high O atoms density, negative ions are efficiently destroyed in the discharge afterglow. As a result, the decay of plasma in the afterglow is determined by electron-ion and ion-ion recombination, and the electron density in the region of high Oatoms density remains relatively high between the pulses. This is the reason why the next pulse does not lead to the streamer formation, but instead the Townsend mechanism of the discharge is initiated. An increase of vibrational temperature of nitrogen molecules at the periphery of plasma channel at time delay t = 1 -30 s after the discharge was obtained. This is due to the intense gas heating and as a result, gas-dynamic expansion of a hot gas channel. Vibrationally excited N 2 (v) molecules produced near the discharge axis moves from the axial region to the periphery. Consequently, at the periphery the vibrational temperature of nitrogen molecules is increased.