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Experimental and modelling study of 1CH2 in premixed very rich methane flames

Fomin, Alexey; Zavlev, Tatyana; Alekseev, Vladimir A. LU ; Rahinov, Igor; Cheskis, Sergey and Konnov, Alexander A. LU (2016) In Combustion and Flame 171. p.198-210
Abstract

Stoichiometric and very rich (1.5 ≤ ɸ ≤ 1.9) laminar flat flames of methane have been investigated using nonintrusive laser diagnostics. Premixed CH4 + O2 + N2 flames were stabilized at a pressure of 30 ± 0.3 Torr. Temperature profiles were obtained using laser-induced fluorescence of OH. Absolute concentration profiles of singlet methylene, 1CH2, were measured by intracavity laser absorption spectroscopy. Uncertainties of the relative and absolute concentrations of singlet methylene were evaluated to be about ±10% and ±30%, respectively. These new experimental data were compared with predictions of three detailed kinetic mechanisms: GRI-mech. 3.0, Aramco mech. 1.3, and the model... (More)

Stoichiometric and very rich (1.5 ≤ ɸ ≤ 1.9) laminar flat flames of methane have been investigated using nonintrusive laser diagnostics. Premixed CH4 + O2 + N2 flames were stabilized at a pressure of 30 ± 0.3 Torr. Temperature profiles were obtained using laser-induced fluorescence of OH. Absolute concentration profiles of singlet methylene, 1CH2, were measured by intracavity laser absorption spectroscopy. Uncertainties of the relative and absolute concentrations of singlet methylene were evaluated to be about ±10% and ±30%, respectively. These new experimental data were compared with predictions of three detailed kinetic mechanisms: GRI-mech. 3.0, Aramco mech. 1.3, and the model under development in Lund. In the last mechanism 78 rate constants of reactions along the pathway CH3 → 1CH2 → 3CH2 → CH were reviewed and updated. No adjustment or tuning of the rate expressions to accommodate experimental results was attempted. GRI-mech. significantly overpredicts singlet methylene concentrations in all flames. Aramco mech. and the present model are in good agreement with the measurements in stoichiometric flame, while in all rich flames only the present mechanism reproduces spatial profiles of 1CH2. Detailed analysis of the behaviour of these models revealed that omission of the reaction 1CH2 + M = 3CH2 + M is the main reason of the discrepancy between predictions of the Aramco 1.3 and GRI-mech. 3.0 and experimental 1CH2 concentrations in rich flames.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Flame, ICLAS, LIF, Methane, Methylene, Modelling
in
Combustion and Flame
volume
171
pages
13 pages
publisher
Elsevier
external identifiers
  • scopus:84977676041
  • wos:000382513000018
ISSN
0010-2180
DOI
10.1016/j.combustflame.2016.06.020
language
English
LU publication?
yes
id
b26ee01e-9646-4f1e-86d0-60158480d0a0
date added to LUP
2016-11-23 11:43:12
date last changed
2017-10-22 05:22:19
@article{b26ee01e-9646-4f1e-86d0-60158480d0a0,
  abstract     = {<p>Stoichiometric and very rich (1.5 ≤ ɸ ≤ 1.9) laminar flat flames of methane have been investigated using nonintrusive laser diagnostics. Premixed CH<sub>4</sub> + O<sub>2</sub> + N<sub>2</sub> flames were stabilized at a pressure of 30 ± 0.3 Torr. Temperature profiles were obtained using laser-induced fluorescence of OH. Absolute concentration profiles of singlet methylene, <sup>1</sup>CH<sub>2</sub>, were measured by intracavity laser absorption spectroscopy. Uncertainties of the relative and absolute concentrations of singlet methylene were evaluated to be about ±10% and ±30%, respectively. These new experimental data were compared with predictions of three detailed kinetic mechanisms: GRI-mech. 3.0, Aramco mech. 1.3, and the model under development in Lund. In the last mechanism 78 rate constants of reactions along the pathway CH<sub>3</sub> → <sup>1</sup>CH<sub>2</sub> → <sup>3</sup>CH<sub>2</sub> → CH were reviewed and updated. No adjustment or tuning of the rate expressions to accommodate experimental results was attempted. GRI-mech. significantly overpredicts singlet methylene concentrations in all flames. Aramco mech. and the present model are in good agreement with the measurements in stoichiometric flame, while in all rich flames only the present mechanism reproduces spatial profiles of <sup>1</sup>CH<sub>2</sub>. Detailed analysis of the behaviour of these models revealed that omission of the reaction <sup>1</sup>CH<sub>2</sub> + M = <sup>3</sup>CH<sub>2</sub> + M is the main reason of the discrepancy between predictions of the Aramco 1.3 and GRI-mech. 3.0 and experimental <sup>1</sup>CH<sub>2</sub> concentrations in rich flames.</p>},
  author       = {Fomin, Alexey and Zavlev, Tatyana and Alekseev, Vladimir A. and Rahinov, Igor and Cheskis, Sergey and Konnov, Alexander A.},
  issn         = {0010-2180},
  keyword      = {Flame,ICLAS,LIF,Methane,Methylene,Modelling},
  language     = {eng},
  month        = {09},
  pages        = {198--210},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Experimental and modelling study of <sup>1</sup>CH<sub>2</sub> in premixed very rich methane flames},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2016.06.020},
  volume       = {171},
  year         = {2016},
}