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Distributed reactions in highly turbulent premixed methane/air flames Part I. Flame structure characterization

Zhou, Bo LU ; Brackmann, Christian LU ; Li, Qing LU ; Wang, Zhenkan LU ; Petersson, Per LU ; Li, Zhongshan LU ; Aldén, Marcus LU and Bai, Xue-Song LU (2015) In Combustion and Flame 162(7). p.2937-2953
Abstract
Simultaneous planar laser-induced fluorescence (PLIF) measurements of a series of reactive scalars and Rayleigh scattering measurements of temperature, i.e. CH/CH2O/OH, HCO/CH2O/OH and T/CH2O/OH, and laser Doppler anemometry (LDA) measurements are carried out to characterize the flame/turbulence interaction in various regimes of turbulent combustion, including the laminar flamelet regime, the thin reaction zone (TRZ) regime, and the distributed reaction zone (DRZ) regime. A series of turbulent pre-mixed methane/air jet flames with different jet speeds and equivalence ratios are studied. The jet Reynolds number ranges from 6000 to 40,000 and the Karlovitz number (Ka) of the studied flames varies from 25 to 1470. It is shown that in the TRZ... (More)
Simultaneous planar laser-induced fluorescence (PLIF) measurements of a series of reactive scalars and Rayleigh scattering measurements of temperature, i.e. CH/CH2O/OH, HCO/CH2O/OH and T/CH2O/OH, and laser Doppler anemometry (LDA) measurements are carried out to characterize the flame/turbulence interaction in various regimes of turbulent combustion, including the laminar flamelet regime, the thin reaction zone (TRZ) regime, and the distributed reaction zone (DRZ) regime. A series of turbulent pre-mixed methane/air jet flames with different jet speeds and equivalence ratios are studied. The jet Reynolds number ranges from 6000 to 40,000 and the Karlovitz number (Ka) of the studied flames varies from 25 to 1470. It is shown that in the TRZ regime CH/HCO layer remain thin but the layer of CH2O and temperature gradient are broadened owing to the rapid turbulence transport. In the DRZ regime the CH and HCO layers are also broadened owing to the rapid transport of reactive species such as OH radicals from the high temperature regions where these radicals are formed to the low temperature region. In the DRZ regime CH and HCO are found to coexist with OH or CH2O owing to the rapid turbulence eddy interaction, which differs fundamentally from that in the TRZ regime and the laminar flamelet regime. For the present investigated flames, the temperature range for the distributed reaction to occur is found to be between 1100 K and 1500 K. It is shown that the structures of flames in different regimes can affect the turbulence field differently. In the DRZ regime the temperature gradient is lower than that in the laminar flamelet and the TRZ regimes, which results in a lower peak of turbulence intensity owing to the retarded velocity gradient across the flames and thereby a lower rate of turbulence production. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
PLIF, Distributed reaction zone regime, Turbulent premixed flames, LDV, Flame/turbulence interaction, Borghi diagram
in
Combustion and Flame
volume
162
issue
7
pages
2937 - 2953
publisher
Elsevier
external identifiers
  • wos:000356028600016
  • scopus:84929947004
ISSN
0010-2180
DOI
10.1016/j.combustflame.2014.12.021
language
English
LU publication?
yes
id
2b23663a-10c1-4ada-9a66-b399d0e5fcbc (old id 7602074)
date added to LUP
2015-07-22 15:47:58
date last changed
2017-11-19 04:02:52
@article{2b23663a-10c1-4ada-9a66-b399d0e5fcbc,
  abstract     = {Simultaneous planar laser-induced fluorescence (PLIF) measurements of a series of reactive scalars and Rayleigh scattering measurements of temperature, i.e. CH/CH2O/OH, HCO/CH2O/OH and T/CH2O/OH, and laser Doppler anemometry (LDA) measurements are carried out to characterize the flame/turbulence interaction in various regimes of turbulent combustion, including the laminar flamelet regime, the thin reaction zone (TRZ) regime, and the distributed reaction zone (DRZ) regime. A series of turbulent pre-mixed methane/air jet flames with different jet speeds and equivalence ratios are studied. The jet Reynolds number ranges from 6000 to 40,000 and the Karlovitz number (Ka) of the studied flames varies from 25 to 1470. It is shown that in the TRZ regime CH/HCO layer remain thin but the layer of CH2O and temperature gradient are broadened owing to the rapid turbulence transport. In the DRZ regime the CH and HCO layers are also broadened owing to the rapid transport of reactive species such as OH radicals from the high temperature regions where these radicals are formed to the low temperature region. In the DRZ regime CH and HCO are found to coexist with OH or CH2O owing to the rapid turbulence eddy interaction, which differs fundamentally from that in the TRZ regime and the laminar flamelet regime. For the present investigated flames, the temperature range for the distributed reaction to occur is found to be between 1100 K and 1500 K. It is shown that the structures of flames in different regimes can affect the turbulence field differently. In the DRZ regime the temperature gradient is lower than that in the laminar flamelet and the TRZ regimes, which results in a lower peak of turbulence intensity owing to the retarded velocity gradient across the flames and thereby a lower rate of turbulence production.},
  author       = {Zhou, Bo and Brackmann, Christian and Li, Qing and Wang, Zhenkan and Petersson, Per and Li, Zhongshan and Aldén, Marcus and Bai, Xue-Song},
  issn         = {0010-2180},
  keyword      = {PLIF,Distributed reaction zone regime,Turbulent premixed flames,LDV,Flame/turbulence interaction,Borghi diagram},
  language     = {eng},
  number       = {7},
  pages        = {2937--2953},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Distributed reactions in highly turbulent premixed methane/air flames Part I. Flame structure characterization},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2014.12.021},
  volume       = {162},
  year         = {2015},
}