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Rotational CARS thermometry in diffusion flames: On the influence of nitrogen spectral line-broadening by CH4 and H-2

Bohlin, Alexis LU and Bengtsson, Per-Erik LU (2011) In Proceedings of the Combustion Institute 33. p.823-830
Abstract
Rotational CARS N-2 thermometry has been developed for improved accuracy in spatial flame regions with high concentrations of either H-2 or CH4, which are typical conditions on the fuel side of diffusion flames. In initial validation experiments up to 700 K, rotational CARS measurements were performed in binary mixtures of H-2 and N-2. Subsequent spectral evaluation with commonly used N-2-N-2 Raman line widths clearly underestimated the real temperatures. Inclusion of recently calculated N-2-H-2 spectral line-broadening coefficients weighted by the concentration of hydrogen resulted in CARS temperatures in much better agreement with the true temperatures. Based on this validation work, improved temperature accuracy was achieved in flame... (More)
Rotational CARS N-2 thermometry has been developed for improved accuracy in spatial flame regions with high concentrations of either H-2 or CH4, which are typical conditions on the fuel side of diffusion flames. In initial validation experiments up to 700 K, rotational CARS measurements were performed in binary mixtures of H-2 and N-2. Subsequent spectral evaluation with commonly used N-2-N-2 Raman line widths clearly underestimated the real temperatures. Inclusion of recently calculated N-2-H-2 spectral line-broadening coefficients weighted by the concentration of hydrogen resulted in CARS temperatures in much better agreement with the true temperatures. Based on this validation work, improved temperature accuracy was achieved in flame measurements on the fuel side of a hydrogen diffusion flame by probing nitrogen simultaneously with the detection of the hydrogen S-0-transition at 354 cm(-1), and weighting the species specific Raman line widths with the information of relative concentration. The validation experiments were repeated for binary mixtures of nitrogen and methane up to 500 K. It was shown that N-2-N-2 Raman line widths gave reproducible temperatures independent of methane concentration in binary mixtures with nitrogen, thus no explicit knowledge on N-2-CH4 Raman line widths is needed for this temperature region. In general, the impact of Raman line widths for accurate rotational CARS thermometry is demonstrated. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Rotational CARS thermometry, Non-linear spectroscopy, Raman line, widths, Diffusion flame
in
Proceedings of the Combustion Institute
volume
33
pages
823 - 830
publisher
Elsevier
external identifiers
  • wos:000285780200087
  • scopus:78650861403
ISSN
1540-7489
DOI
10.1016/j.proci.2010.05.023
language
English
LU publication?
yes
id
78072eed-8c95-438a-989c-0910f284bff6 (old id 1870173)
date added to LUP
2011-04-19 11:01:48
date last changed
2017-04-23 03:20:25
@article{78072eed-8c95-438a-989c-0910f284bff6,
  abstract     = {Rotational CARS N-2 thermometry has been developed for improved accuracy in spatial flame regions with high concentrations of either H-2 or CH4, which are typical conditions on the fuel side of diffusion flames. In initial validation experiments up to 700 K, rotational CARS measurements were performed in binary mixtures of H-2 and N-2. Subsequent spectral evaluation with commonly used N-2-N-2 Raman line widths clearly underestimated the real temperatures. Inclusion of recently calculated N-2-H-2 spectral line-broadening coefficients weighted by the concentration of hydrogen resulted in CARS temperatures in much better agreement with the true temperatures. Based on this validation work, improved temperature accuracy was achieved in flame measurements on the fuel side of a hydrogen diffusion flame by probing nitrogen simultaneously with the detection of the hydrogen S-0-transition at 354 cm(-1), and weighting the species specific Raman line widths with the information of relative concentration. The validation experiments were repeated for binary mixtures of nitrogen and methane up to 500 K. It was shown that N-2-N-2 Raman line widths gave reproducible temperatures independent of methane concentration in binary mixtures with nitrogen, thus no explicit knowledge on N-2-CH4 Raman line widths is needed for this temperature region. In general, the impact of Raman line widths for accurate rotational CARS thermometry is demonstrated. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.},
  author       = {Bohlin, Alexis and Bengtsson, Per-Erik},
  issn         = {1540-7489},
  keyword      = {Rotational CARS thermometry,Non-linear spectroscopy,Raman line,widths,Diffusion flame},
  language     = {eng},
  pages        = {823--830},
  publisher    = {Elsevier},
  series       = {Proceedings of the Combustion Institute},
  title        = {Rotational CARS thermometry in diffusion flames: On the influence of nitrogen spectral line-broadening by CH4 and H-2},
  url          = {http://dx.doi.org/10.1016/j.proci.2010.05.023},
  volume       = {33},
  year         = {2011},
}