Plasma-assisted stabilization of laminar premixed methane/air flames around the lean flammability limit

Bak, Moon Soo; Do, Hyungrok; Mungal, M. G.; Cappelli, Mark A.

doi:10.1016/j.combustflame.2012.03.023

Cited by 100 publications

(53 citation statements)

References 20 publications

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“…(11)(12)(13) were chosen in accordance with the assumptions that the central discharge region is axisymmetric and the gas parameters at the outer boundary of the computation region, r = R, are unperturbed,…”

Section: Model Descriptionmentioning

confidence: 99%

“…ecent increased interest in studying of pulsed nanosecond discharges arises from their application for solving plasma-related problems in aerodynamics [1][2][3][4][5], for ignition of combustible mixtures [6][7][8][9][10][11][12][13][14][15], etc. Gas-discharge plasma affects the ignition via the production of chemically active particles and gas heating.…”

Section: Introductionmentioning

confidence: 99%

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

Попов

2015

53rd AIAA Aerospace Sciences Meeting

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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.

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Section: Model Descriptionmentioning

confidence: 99%

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

Попов

2015

53rd AIAA Aerospace Sciences Meeting

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“…The violet bands of CN radicals further displayed that the N 2 molecules, N atoms or N ions were involved in the reactions with CH 4 . Nevertheless, these indispensable intermediate species and the related reactions in NPD were not found in the existing kinetic simulations of the nanosecond pulsed discharges for methane/air combustion, such as GRI-Mech mechanism [26], 2-D kinetic simulations [27].…”

Section: The Time Resolved Emission Spectra Of Npd In the Bunsen Flamementioning

confidence: 99%

Experimental Study of the Transient Response of Bunsen Flame to Nanosecond Pulsed Discharges

Zhang

Xiong

et al. 2015

Plasma Chem Plasma Process

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The transient processes associated with the interaction of a Bunsen flame and nanosecond pulsed discharges (NPD) are explored experimentally with two optical methods. A nanosecond-gated schlieren system is employed to image the shockwave propagation and the hydrodynamic response of the flame to NPD while the time-resolved optical emission spectroscopy measurements are carried out to determine active species and temperature in the plasma region created by the discharges. Therefore, the unsteady process of the interaction of the flame with the discharges is recorded in real-time by the combined measurements. Numbers of experimental evidences for understanding the dynamics of non-equilibrium plasma produced by NPD and performing further numerical simulation are offered.

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“…The electron-impact cross sections for N 2 [20] [24] are taken from databases compiled from different sources. All rate coefficients except the electron-impact reactions are adopted from the previous literature [9,17,18,[25][26][27][28][29], whereas the rate coefficients of the electron-impact reactions, electron mobility and electron temperature are calculated as a function of the reduced electric field (E/n) using the Bolsig+ software package [30]. …”

Section: Simulationsmentioning

confidence: 99%

“…Among these non-equilibrium plasma sources, nanosecond-pulsed repetitive discharges have been used because of their effectiveness in creating high-density plasmas with a lower required power budget when compared with other types of plasmas [4]. Studies have shown that these discharges are effective in shortening ignition delay times [5,6] and in flame holding [7][8][9]. This enhanced flame stability has been attributed to the production of radicals such as atomic oxygen (O) in significant amounts within the plasma [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Numerical studies of nitric oxide formation in nanosecond-pulsed discharge-stabilized flames of premixed methane/air

Bak

Cappelli

2015

Phil. Trans. R. Soc. A.

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One contribution of 14 to a theme issue 'Physics and chemistry of plasma-assisted combustion' . A simulation is developed to investigate the kinetics of nitric oxide (NO) formation in premixed methane/air combustion stabilized by nanosecondpulsed discharges. The simulation consists of two connected parts. The first part calculates the kinetics within the discharge while considering both plasma/combustion reactions and species diffusion, advection and thermal conduction to the surrounding flow. The second part calculates the kinetics of the overall flow after mixing the discharge flow with the surrounding flow to account for the effect that the discharge has on the overall kinetics. The simulation reveals that the discharge produces a significant amount of atomic oxygen (O) as a result of the high discharge temperature and dissociative quenching of excited state nitrogen by molecular oxygen. This atomic oxygen subsequently produces hydroxyl (OH) radicals. The fractions of these O and OH then undergo Zel'dovich reactions and are found to contribute to as much as 73% of the total NO that is produced. The post-discharge simulation shows that the NO survives within the flow once produced.

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Plasma-assisted stabilization of laminar premixed methane/air flames around the lean flammability limit

Cited by 100 publications

References 20 publications

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

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

Experimental Study of the Transient Response of Bunsen Flame to Nanosecond Pulsed Discharges

Numerical studies of nitric oxide formation in nanosecond-pulsed discharge-stabilized flames of premixed methane/air

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