On combustion enhancement mechanisms in the case of electrical-discharge-excited oxygen molecules

Starik, A. M.; Lukhovitskii, B. I.; Naumov, V. V.; Титова, Н. С.

doi:10.1134/s1063784207100064

Cited by 13 publications

(18 citation statements)

References 12 publications

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“…Therefore, the measurements did not provide quantitative concentrations of all the major species of enhancement in the system. Even though the experiments were the first of their kind in an attempt to isolate the effect of O 2 (a 1 D g ) and the results agreed reasonably well with their previous calculations [36,37] it was not certain whether O 2 (a 1 D g ) was the only species causing the enhancement. In addition, the experiments were conducted only for an H 2 -O 2 mixture.…”

Section: Introductionsupporting

confidence: 56%

Flame propagation enhancement by plasma excitation of oxygen. Part II: Effects of O2(a1Δg)

Ombrello

Won

et al. 2010

Combustion and Flame

203

113

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a b s t r a c tThe isolated effect of O 2 (a 1 D g ) on the propagation of C 2 H 4 lifted flames was studied at reduced pressures (3.61 kPa and 6.73 kPa). The O 2 (a 1 D g ) was produced in a microwave discharge plasma and was isolated from O and O 3 by NO addition to the plasma afterglow in a flow residence time on the order of 1 s. The concentrations of O 2 (a 1 D g ) and O 3 were measured quantitatively through absorption by sensitive off-axis integrated-cavity-output spectroscopy and one-pass line-of-sight absorption, respectively. Under these conditions, it was found that O 2 (a 1 D g ) enhanced the propagation speed of C 2 H 4 lifted flames. Comparison with the results of enhancement by O 3 found in part I of this investigation provided an estimation of 2-3% of flame speed enhancement for 5500 ppm of O 2 (a 1 D g ) addition from the plasma. Numerical simulation results using the current kinetic model of O 2 (a 1 D g ) over-predicts the flame propagation enhancement found in the experiments. However, the inclusion of collisional quenching rate estimations of O 2 (a 1 D g ) by C 2 H 4 mitigated the over-prediction. The present isolated experimental results of the enhancement of a hydrocarbon fueled flame by O 2 (a 1 D g ), along with kinetic modeling results suggest that further studies of C n H m + O 2 (a 1 D g ) collisional and reactive quenching are required in order to correctly predict combustion enhancement by O 2 (a 1 D g ). The present experimental results will have a direct impact on the development of elementary reaction rates with O 2 (a 1 D g ) at flame conditions to establish detailed plasma-flame kinetic mechanisms.

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Section: Introductionsupporting

confidence: 56%

Flame propagation enhancement by plasma excitation of oxygen. Part II: Effects of O2(a1Δg)

Ombrello

Won

et al. 2010

Combustion and Flame

203

113

View full text Add to dashboard Cite

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“…In order to isolate the effect of O and O 3 , Hg and its oxide (HgO) were injected into the flow; however, the concentration of O 3 was not measured, and O 2 (a 1 Δ g ) was measured only through emission intensity. The measurements did not provide quantitative concentrations of all the major species of enhancement in the system, although it was the first attempt to isolate the effect of O 2 (a 1 Δ g ) and the results agreed reasonably well with their previous calculations [43,44]. In addition, the experiments were conducted only for a H 2 -O 2 mixture.…”

Section: Introductionsupporting

confidence: 63%

Development of Non-Equilibrium Plasma-Flame Kinetic Mechanism and its Validation Using Gliding Arc Integrated with Counterflow Burner

Ju¹,

Ombrello²,

Fridman³

2010

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“…In fact, in order to excite the lower vibrational state of O 2 molecules one should spend 0.193 eV; the excitation of the lower singlet electronic state requires 0.98 eV, while production of O atoms as a result of dissociation of O 2 molecules in the ground X 3 − g state by electron impact requires 5.1 eV. Moreover, as recently predicted in [9], the excitation of O 2 molecules to the a 1 g and b 1 + g states in electrical discharge may markedly decrease the ignition temperature, reduce the induction time and increase the completeness of combustion in an H 2 -O 2 mixture.…”

Section: Introductionmentioning

confidence: 82%

“…Estimates based on the numerical modelling of combustion kinetics in the H 2 -O 2 mixture with the reaction mechanism [13] at a pressure of 10 Torr and a temperature of 800 K have shown that if the oxygen flow contains 5% of O 2 (a 1 g ) molecules one can expect the shortening of the induction zone length by a factor of 5. This effect is caused by accelerating the chain-branching due to the appearance of novel pathways of the production of highly reactive O and H atoms and OH radicals in the course of reactions with the electronically excited oxygen molecules [9]. Hence, the displacement of the flame zone front along the reactor axis, which should follow the igniting or switching off of the discharge, was taken as a criterion of the influence of the abundance of singlet oxygen molecules in the mixture on the induction zone length.…”

Section: Methodology Of the Experimentsmentioning

confidence: 99%

“…Various approaches have been proposed to enhance the ignition and combustion in hydrogen-oxygen and hydrocarbon-oxygen mixtures by means of the electrical discharge. These approaches may be grouped as follows: heating of a mixture by plasma torch or arc [3,4], generation in appreciable amounts of chemically active atoms and radicals due to electron impact dissociation of reactants [5,6] and excitation of molecules to vibrational and electronic states by a specially arranged electrical discharge [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the influence of electronically excited oxygen molecules on combustion of hydrogen–oxygen mixture

Смирнов

Stelmakh

Fabelinsky

et al. 2008

J. Phys. D: Appl. Phys.

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This communication reports on the experimental observation of the shortening of the induction zone length in a premixed mode of combustion in a subsonic H2–O2 low pressure flow due to the presence of oxygen molecules excited to the singlet a 1Δg electronic state. The low pressure electric glow discharge was used to produce singlet oxygen molecules. The analysis showed that even a small number of O2(a 1Δg) molecules (∼1%) in the H2–O2 mixture allows one to noticeably reduce the ignition delay length and to ignite the mixture at a lower temperature. The results obtained exhibit the possibility to intensify the combustion of a hydrogen–oxygen mixture by means of excitation of O2 molecules by electrical discharge at low pressure (P = 10–20 Torr).

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On combustion enhancement mechanisms in the case of electrical-discharge-excited oxygen molecules

Cited by 13 publications

References 12 publications

Flame propagation enhancement by plasma excitation of oxygen. Part II: Effects of O2(a1Δg)

Flame propagation enhancement by plasma excitation of oxygen. Part II: Effects of O2(a1Δg)

Development of Non-Equilibrium Plasma-Flame Kinetic Mechanism and its Validation Using Gliding Arc Integrated with Counterflow Burner

On the influence of electronically excited oxygen molecules on combustion of hydrogen–oxygen mixture

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