Kinetics of ignition of saturated hydrocarbons by nonequilibrium plasma: C2H6- to C5H12-containing mixtures

Kosarev, I. B.; Aleksandrov, N. L.; Kindysheva, Svetlana; Starikovskaia, Svetlana; Starikovskii, Andrei

doi:10.1016/j.combustflame.2008.07.013

Cited by 125 publications

(65 citation statements)

References 43 publications

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“…Additional time-resolved data on key radical species number densities, such as H, OH and O, over a wide range of equivalence ratios (from fuel-lean to fuel-rich mixtures), measured prior to ignition, would considerably expand parameter space for the mechanism validation. Finally, complementing this approach by ignition delay time measurements at high-temperature conditions (above autoignition temperature), such as in fuel-air mixtures preheated behind a reflected shock in a shock tube [49,50] may considerably improve predictive capability of the mechanism. Finally, detailed sensitivity analysis to identify reduced reaction mechanisms for individual hydrocarbons is extremely critical, since kinetic modelling of coupled nanosecond pulse discharge dynamics, energy transfer in the plasma and plasma-assisted combustion for long discharge pulse bursts requires incorporating a wide range of time scales, approximately 10 −12 -10 −2 s, which becomes very computationally intensive even for one-dimensional geometry [33,51] and especially for two-dimensional geometries.…”

Section: Discussionmentioning

confidence: 99%

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas

Adamovich

Lempert

2015

Phil. Trans. R. Soc. A.

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This work describes the kinetic mechanism of coupled molecular energy transfer and chemical reactions in low-temperature air, H 2 –air and hydrocarbon–air plasmas sustained by nanosecond pulse discharges (single-pulse or repetitive pulse burst). The model incorporates electron impact processes, state-specific N 2 vibrational energy transfer, reactions of excited electronic species of N 2 , O 2 , N and O, and ‘conventional’ chemical reactions (Konnov mechanism). Effects of diffusion and conduction heat transfer, energy coupled to the cathode layer and gasdynamic compression/expansion are incorporated as quasi-zero-dimensional corrections. The model is exercised using a combination of freeware (Bolsig+) and commercial software (ChemKin-Pro). The model predictions are validated using time-resolved measurements of temperature and N 2 vibrational level populations in nanosecond pulse discharges in air in plane-to-plane and sphere-to-sphere geometry; temperature and OH number density after nanosecond pulse burst discharges in lean H 2 –air, CH 4 –air and C 2 H 4 –air mixtures; and temperature after the nanosecond pulse discharge burst during plasma-assisted ignition of lean H 2 -mixtures, showing good agreement with the data. The model predictions for OH number density in lean C 3 H 8 –air mixtures differ from the experimental results, over-predicting its absolute value and failing to predict transient OH rise and decay after the discharge burst. The agreement with the data for C 3 H 8 –air is improved considerably if a different conventional hydrocarbon chemistry reaction set (LLNL methane– n -butane flame mechanism) is used. The results of mechanism validation demonstrate its applicability for analysis of plasma chemical oxidation and ignition of low-temperature H 2 –air, CH 4 –air and C 2 H 4 –air mixtures using nanosecond pulse discharges. Kinetic modelling of low-temperature plasma excited propane–air mixtures demonstrates the need for development of a more accurate ‘conventional’ chemistry mechanism.

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Section: Discussionmentioning

confidence: 99%

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas

Adamovich

Lempert

2015

Phil. Trans. R. Soc. A.

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“…Mechanistic data provided by past investigations into the kinetics of PAC for alkane oxidation [4][5][6][7][8][9][10][11][12] have been constrained by the operating limits of a given experiment. For example, a series of papers have been published combining both experimental and numerical results using the shock-tube technique (T = 880-1970 K and P = 0.2-2.2 atm) [6][7][8][9] and more recently using a rapid-compression machine (T = 665-960 K and P = 7.5-15 atm) [10,11].…”

Section: Introductionmentioning

confidence: 99%

Flow reactor studies of non-equilibrium plasma-assisted oxidation of n -alkanes

Tsolas

Lee

Yetter

2015

Phil. Trans. R. Soc. A.

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The oxidation of n -alkanes (C 1 –C 7 ) has been studied with and without the effects of a nanosecond, non-equilibrium plasma discharge at 1 atm pressure from 420 to 1250 K. Experiments have been performed under nearly isothermal conditions in a flow reactor, where reactive mixtures are diluted in Ar to minimize temperature changes from chemical reactions. Sample extraction performed at the exit of the reactor captures product and intermediate species and stores them in a multi-position valve for subsequent identification and quantification using gas chromatography. By fixing the flow rate in the reactor and varying the temperature, reactivity maps for the oxidation of fuels are achieved. Considering all the fuels studied, fuel consumption under the effects of the plasma is shown to have been enhanced significantly, particularly for the low-temperature regime ( T <800 K). In fact, multiple transitions in the rates of fuel consumption are observed depending on fuel with the emergence of a negative-temperature-coefficient regime. For all fuels, the temperature for the transition into the high-temperature chemistry is lowered as a consequence of the plasma being able to increase the rate of fuel consumption. Using a phenomenological interpretation of the intermediate species formed, it can be shown that the active particles produced from the plasma enhance alkyl radical formation at all temperatures and enable low-temperature chain branching for fuels C 3 and greater. The significance of this result demonstrates that the plasma provides an opportunity for low-temperature chain branching to occur at reduced pressures, which is typically observed at elevated pressures in thermal induced systems.

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“…The kinetic of propane in non-thermal plasmas of atmospheric gases (N 2 /O 2 /H 2 O mixtures) is currently under study owing to various applications such as cleaning of polluted air streams [1][2][3][4][5][6], or more recently plasma assisted ignition and combustion [7][8][9][10][11][12][13]. Owing to other types of previously developed applications of low pressure plasmas, for example carbon compounds thin films production [14], numerous works have been performed in the past about electron collisions on this hydrocarbon molecule [15][16][17][18], especially on ionisation processes.…”

Section: Introductionmentioning

confidence: 99%

Propane dissociation in a non-thermal high-pressure nitrogen plasma

Moreau¹,

Pasquiers²,

Blin-Simiand³

et al. 2010

J. Phys. D: Appl. Phys.

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Abstract. The removal and the conversion processes of propane in N 2 /C 3 H 8 mixtures (concentration of hydrocarbon molecules up to 5500 ppm) energised by a photo-triggered discharge (homogeneous plasma) are studied at 460 mbar total pressure, both experimentally and theoretically. A self-consistent 0D discharge and kinetic model is used to interpret chromatographic measurements of propane and some by-products concentrations (hydrogen and hydrocarbons with 2 or 3 carbon atoms). It is suggested, from the comparison between measurements and model predictions, that quenching processes of nitrogen metastable states by C 3 H 8 lead to the dissociation of the hydrocarbon molecule, and are the most important processes for the removal of propane. Such a result is obtained using the quenching coefficient value previously determined by Callear and Wood for the A 3 Σ + u state [19], whereas the coefficient for collisions of the singlet states with C 3 H 8 is estimated to be 3.0x10 -10 cm 3 s -1 in order to explain the measured propane disappearance in the N 2 / C 3 H 8 mixture excited by the photo-triggered discharge. The hydrogen molecule is the measured most populated by-product and, also from the comparison between experimental results and model predictions, the most probable dissociation products of propane appear to be H 2 and C 3 H 6 . The propene molecule is also efficiently dissociated by quenching processes of N 2 states, and probably leads to the production of hydrogen atoms and methyl radicals with equivalent probabilities. The kinetic model predicts that the carbon atom is distributed amongst numerous molecules, including HCN, CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , C 3 H 6 .

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Kinetics of ignition of saturated hydrocarbons by nonequilibrium plasma: C2H6- to C5H12-containing mixtures

Cited by 125 publications

References 43 publications

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas

Flow reactor studies of non-equilibrium plasma-assisted oxidation of n -alkanes

Propane dissociation in a non-thermal high-pressure nitrogen plasma

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