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Soot visualisation by use of laser-induced soot vapourisation in combination with polarisation spectroscopy

Walewski, Joachim LU ; Rupinski, M; Bladh, Henrik LU ; Li, Zhongshan LU ; Bengtsson, Per-Erik LU and Aldén, Marcus LU (2003) In Applied Physics B 77(4). p.447-454
Abstract
A novel approach to the visualisation of soot is presented. It relies on a combination of laser-induced soot vapourisation and consecutive polarisation spectroscopy. Upon soot vapourisation, molecular fragments (for example, C-2) emerge, and may serve as effective tracers for soot. In this study we demonstrate that saturated polarisation spectroscopy on photoinduced C-2 can be exploited for soot detection. Signal maps featuring high signal-to-noise ratios were readily recorded in ethyne-rich flames and any spurious background, for example, caused by Rayleigh scattering, was successfully suppressed by means of spatial filtering. Additionally, investigations were carried out addressing how the attained signals correlate with local soot... (More)
A novel approach to the visualisation of soot is presented. It relies on a combination of laser-induced soot vapourisation and consecutive polarisation spectroscopy. Upon soot vapourisation, molecular fragments (for example, C-2) emerge, and may serve as effective tracers for soot. In this study we demonstrate that saturated polarisation spectroscopy on photoinduced C-2 can be exploited for soot detection. Signal maps featuring high signal-to-noise ratios were readily recorded in ethyne-rich flames and any spurious background, for example, caused by Rayleigh scattering, was successfully suppressed by means of spatial filtering. Additionally, investigations were carried out addressing how the attained signals correlate with local soot volumne fractions. For this purpose, height profiles of C-2 number densities inferred from the polarisation spectroscopy signal maps were compared with profiles of the soot volumne fraction inferred from measurements with laser-induced incandescence. For low soot volumne fractions, the shapes of the height profiles from our approach agree rather well with the latter; they do not agree for higher soot volumne fractions. Further investigation is required to resolve this discrepancy. Scattering from particles in the Mie scattering range may hamper the application of this approach, and avenues are suggested for extending the applicability of the approach presented to large soot particles. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Applied Physics B
volume
77
issue
4
pages
447 - 454
publisher
Springer
external identifiers
  • wos:000186179100014
  • scopus:0142185294
ISSN
0946-2171
DOI
10.1007/s00340-003-1277-5
language
English
LU publication?
yes
id
331b59f6-d972-49a6-9aaa-1781c2cb4c12 (old id 297411)
date added to LUP
2007-09-23 14:22:16
date last changed
2018-01-07 05:44:50
@article{331b59f6-d972-49a6-9aaa-1781c2cb4c12,
  abstract     = {A novel approach to the visualisation of soot is presented. It relies on a combination of laser-induced soot vapourisation and consecutive polarisation spectroscopy. Upon soot vapourisation, molecular fragments (for example, C-2) emerge, and may serve as effective tracers for soot. In this study we demonstrate that saturated polarisation spectroscopy on photoinduced C-2 can be exploited for soot detection. Signal maps featuring high signal-to-noise ratios were readily recorded in ethyne-rich flames and any spurious background, for example, caused by Rayleigh scattering, was successfully suppressed by means of spatial filtering. Additionally, investigations were carried out addressing how the attained signals correlate with local soot volumne fractions. For this purpose, height profiles of C-2 number densities inferred from the polarisation spectroscopy signal maps were compared with profiles of the soot volumne fraction inferred from measurements with laser-induced incandescence. For low soot volumne fractions, the shapes of the height profiles from our approach agree rather well with the latter; they do not agree for higher soot volumne fractions. Further investigation is required to resolve this discrepancy. Scattering from particles in the Mie scattering range may hamper the application of this approach, and avenues are suggested for extending the applicability of the approach presented to large soot particles.},
  author       = {Walewski, Joachim and Rupinski, M and Bladh, Henrik and Li, Zhongshan and Bengtsson, Per-Erik and Aldén, Marcus},
  issn         = {0946-2171},
  language     = {eng},
  number       = {4},
  pages        = {447--454},
  publisher    = {Springer},
  series       = {Applied Physics B},
  title        = {Soot visualisation by use of laser-induced soot vapourisation in combination with polarisation spectroscopy},
  url          = {http://dx.doi.org/10.1007/s00340-003-1277-5},
  volume       = {77},
  year         = {2003},
}