On the role of excited species in hydrogen combustion

Konnov, Alexander A.

doi:10.1016/j.combustflame.2015.07.014

Cited by 66 publications

(37 citation statements)

References 187 publications

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“…Konnov's kinetic model 20 with the kinetic information obtained in this work for the reactions OH + HO2 → H2O + O2( 3 Σ g − ) and OH + HO2 → H2O + O2( 1 ∆g).…”

Section: Numerical Simulations Of the H2o2 Decompositionmentioning

confidence: 54%

“…Thus, the H2O2 decomposition at 1182 K and 1.672 atm is not significantly affected when the new rate constants for OH + HO2 → H2O + O2( 1 ∆g) are included in the kinetic model developed by Konnov. 20 We performed the same simulations at 1000 K, 1500 K and 1800 K and observed no differences in the H2O2 decomposition using Konnov…”

Section: Role Of the O2( 1 ∆G) In H2o2 Decomposition And In Cmentioning

confidence: 90%

“…Using these rate constants we updated the kinetic model recently developed by Konnov,20 which includes the rate constants from González et al 2 (singlet channel) and Hong et al 15 (triplet channel), to simulate the shock waves experiment by Hong et al 15 for H2O2 decomposition using CHEMKIN-PRO. The model was also used to estimate flame speeds and ignition delay times of different H2-oxidizer mixtures.…”

Section: Discussionmentioning

confidence: 99%

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Ab initio and transition state theory study of the OH + HO₂ → H₂O + O₂(³Σ_g⁻)/O₂(¹Δ_g) reactions: yield and role of O₂(¹Δ_g) in H₂O₂ decomposition and in combustion of H₂

Monge‐Palacios

Sarathy

2018

Phys. Chem. Chem. Phys.

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Reactions of hydroxyl (OH) and hydroperoxyl (HO) are important for governing the reactivity of combustion systems. We performed post-CCSD(T) ab initio calculations at the W3X-L//CCSD = FC/cc-pVTZ level to explore the triplet ground-state and singlet excited-state potential energy surfaces of the OH + HO → HO + O(Σ)/O(Δ) reactions. Using microcanonical and multistructural canonical transition state theories, we calculated the rate constant for the triplet and singlet channels over the temperature range 200-2500 K, represented by k(T) = 3.08 × 10T exp(1151/RT) + 8.00 × 10T exp(-6896/RT) and k(T) = 2.14 × 10T exp(-2180/RT) in cm mol s, respectively. The branching ratios show that the yield of singlet excited oxygen is small (<0.5% below 1000 K). To ascertain the importance of singlet oxygen channel, our new kinetic information was implemented into the kinetic model for hydrogen combustion recently updated by Konnov (Combust. Flame, 2015, 162, 3755-3772). The updated kinetic model was used to perform HO thermal decomposition simulations for comparison against shock tube experiments performed by Hong et al. (Proc. Combust. Inst., 2013, 34, 565-571), and to estimate flame speeds and ignition delay times in H mixtures. The simulation predicted a larger amount of O(Δ) in HO decomposition than that predicted by Konnov's original model. These differences in the O(Δ) yield are due to the use of a higher ab initio level and a more sophisticated methodology to compute the rate constant than those used in previous studies, thereby predicting a significantly larger rate constant. No effect was observed on the rate of the HO decomposition and on the flame speeds and ignition delay times of different H-oxidizer mixtures. However, if the oxidizer is seeded with O, small differences appear in the flame speed. Given that O(Δ) is much more reactive than O(Σ), we do not preclude an effect of the singlet channel of the titled reaction in other combustion systems, especially in systems where excited oxygen plays an important role.

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“…Konnov's kinetic model 20 with the kinetic information obtained in this work for the reactions OH + HO2 → H2O + O2( 3 Σ g − ) and OH + HO2 → H2O + O2( 1 ∆g).…”

Section: Numerical Simulations Of the H2o2 Decompositionmentioning

confidence: 54%

Section: Role Of the O2( 1 ∆G) In H2o2 Decomposition And In Cmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

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Ab initio and transition state theory study of the OH + HO₂ → H₂O + O₂(³Σ_g⁻)/O₂(¹Δ_g) reactions: yield and role of O₂(¹Δ_g) in H₂O₂ decomposition and in combustion of H₂

Monge‐Palacios

Sarathy

2018

Phys. Chem. Chem. Phys.

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“…Gas phase processes with oxygen molecules in second electronically excited state b 1 has been studied extensively in last decades, due to the importance of these processes in the terrestrial atmosphere [1][2][3], oxygen-containing gas discharges [4][5][6] and combustion [7][8][9][10]. Plasma-chemicals processes in the air-fuel mixtures result in formation of O2(b 1 ) molecules that may activates chain reactions in the combustion zones [11].…”

Section: Introductionmentioning

confidence: 99%

Measurements of rate constants of O₂(b) quenching by CH₄, NO, N₂O at temperatures 300-800 K

et al. 2018

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Electronically excited oxygen has an important place in the kinetic schemes of the processes taking place in the atmosphere, in the active medium of an oxygen-iodine laser, and in plasma-assisted combustion 1 . Over the past decades, a large amount of data on the rate constants of quenching O2(b) on a large number of collision partners has been accumulated. However, they mostly refer to the results of measurements at room temperature. In this paper, rate constants for the quenching of O2(b) by collisions with N2O, NO, and CH4 have been determined in the temperature range from 297 to 800 K, by the laserinduced fluorescence method. O2(b) was excited by pulses from a tunable dye laser, and the deactivation kinetics were followed via observing the temporal behavior of the b 1 Σg + → X 3 Σgfluorescence. From the analysis of experimental results, the following temperature dependencies of the quenching rate constants by these gases were obtained, and could be represented by the expressions: kNO=(1.77±0.2)×10 -24 ×T 3.5 exp(1138±37/T); kN2O=(2.63±0.14)×10 -16 ×T 1.5 ×exp(590±26/T) and kCH4=(3.54±0.4)×10 -18 ×T 1.5 ×exp(-220±24/T) cm 3 s -1 . All of the rate constants measured at room temperature were found to be in good agreement with previously reported values.

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“…Active oxygen species (AOS -ozone O3, molecular singlet oxygen O2(a) (0.98 eV) and О2(b) (1.63 eV), atomic oxygen O( 3 P) and O( 1 D) (1.97 eV)) play an important role in the combustion, especially when it is initiated by plasma [1,2]. In recent years, a wide interest to them is because the processes involving AOS can be used to expand the limits of combustion and ignition.…”

Section: Introductionmentioning

confidence: 99%

Ozone recovery in the presence of CO and N₂O

et al. 2018

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Extremely reactive vibrationally excited ozone O3(υ) molecule is formed in excess of O2 in particular in air-fuel mixture, however there is a lack of kinetic data on O3(υ) reactions with combustion products. The time-resolved absorption spectroscopy method was applied for measurements of the O3 recovery rates after 266 nm photolysis in the presence of O, CO and nitrous oxides. It was revealed that reaction O3(υ) + O results in an incomplete ozone recovery. In the reaction O3(υ) + O stabilization channel dominates the reactionary one. In the presence of N2O, ozone does not restore to its initial level.

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On the role of excited species in hydrogen combustion

Cited by 66 publications

References 187 publications

Ab initio and transition state theory study of the OH + HO₂ → H₂O + O₂(³Σ_g⁻)/O₂(¹Δ_g) reactions: yield and role of O₂(¹Δ_g) in H₂O₂ decomposition and in combustion of H₂

Ab initio and transition state theory study of the OH + HO₂ → H₂O + O₂(³Σ_g⁻)/O₂(¹Δ_g) reactions: yield and role of O₂(¹Δ_g) in H₂O₂ decomposition and in combustion of H₂

Measurements of rate constants of O₂(b) quenching by CH₄, NO, N₂O at temperatures 300-800 K

Ozone recovery in the presence of CO and N₂O

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On the role of excited species in hydrogen combustion

Cited by 66 publications

References 187 publications

Ab initio and transition state theory study of the OH + HO2 → H2O + O2(3Σg−)/O2(1Δg) reactions: yield and role of O2(1Δg) in H2O2 decomposition and in combustion of H2

Ab initio and transition state theory study of the OH + HO2 → H2O + O2(3Σg−)/O2(1Δg) reactions: yield and role of O2(1Δg) in H2O2 decomposition and in combustion of H2

Measurements of rate constants of O2(b) quenching by CH4, NO, N2O at temperatures 300-800 K

Ozone recovery in the presence of CO and N2O

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Ab initio and transition state theory study of the OH + HO₂ → H₂O + O₂(³Σ_g⁻)/O₂(¹Δ_g) reactions: yield and role of O₂(¹Δ_g) in H₂O₂ decomposition and in combustion of H₂

Ab initio and transition state theory study of the OH + HO₂ → H₂O + O₂(³Σ_g⁻)/O₂(¹Δ_g) reactions: yield and role of O₂(¹Δ_g) in H₂O₂ decomposition and in combustion of H₂

Measurements of rate constants of O₂(b) quenching by CH₄, NO, N₂O at temperatures 300-800 K

Ozone recovery in the presence of CO and N₂O