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Influence of spatial laser energy distribution on evaluated soot particle sizes using two-colour laser-induced incandescence in a flat premixed ethylene/air flame

Bladh, Henrik LU ; Johnsson, Jonathan LU and Bengtsson, Per-Erik LU (2009) In Applied Physics B 96(4). p.645-656
Abstract
Time-resolved laser-induced incandescence (LII) has been developed rapidly during the last decade as a useful non-intrusive technique for particle size determination. Still several parameters should be investigated in order to improve the accuracy of LII for particle sizing and the spatial distribution of the laser energy is one of these. Generally a top-hat profile is recommended, as this ensures a uniform heating of all particles in the measurement volume. As it is generally not straightforward to create a uniform beam profile, it is of interest to establish the influence of various profiles on the evaluated particle sizes. In this work we present both an experimental and a theoretical investigation of the influence of the spatial... (More)
Time-resolved laser-induced incandescence (LII) has been developed rapidly during the last decade as a useful non-intrusive technique for particle size determination. Still several parameters should be investigated in order to improve the accuracy of LII for particle sizing and the spatial distribution of the laser energy is one of these. Generally a top-hat profile is recommended, as this ensures a uniform heating of all particles in the measurement volume. As it is generally not straightforward to create a uniform beam profile, it is of interest to establish the influence of various profiles on the evaluated particle sizes. In this work we present both an experimental and a theoretical investigation of the influence of the spatial profile on evaluated sizes. All experiments were carried out using a newly developed setup for two-colour LII (2C-LII) which provides online monitoring of both the spatial and temporal profile as well as the laser pulse energy. The LII measurements were performed in a one-dimensional premixed sooting ethylene/air flame, and evaluated particle sizes from LII were compared with thermophoretically sampled soot particles analysed using transmission electron microscopy (TEM). The results show that although there is some influence of the spatial laser energy distribution on the evaluated particle sizes both in modelling and experiments, this effect is substantially smaller than the influence of the uncertainties in gas temperature and the thermal accommodation coefficient. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Physics B
volume
96
issue
4
pages
645 - 656
publisher
Springer
external identifiers
  • wos:000269054800008
  • scopus:69049098050
ISSN
0946-2171
DOI
10.1007/s00340-009-3523-y
language
English
LU publication?
yes
id
ddda878e-87d3-47b1-8a00-d87798bba005 (old id 1477472)
date added to LUP
2009-09-28 14:39:42
date last changed
2017-12-10 03:38:27
@article{ddda878e-87d3-47b1-8a00-d87798bba005,
  abstract     = {Time-resolved laser-induced incandescence (LII) has been developed rapidly during the last decade as a useful non-intrusive technique for particle size determination. Still several parameters should be investigated in order to improve the accuracy of LII for particle sizing and the spatial distribution of the laser energy is one of these. Generally a top-hat profile is recommended, as this ensures a uniform heating of all particles in the measurement volume. As it is generally not straightforward to create a uniform beam profile, it is of interest to establish the influence of various profiles on the evaluated particle sizes. In this work we present both an experimental and a theoretical investigation of the influence of the spatial profile on evaluated sizes. All experiments were carried out using a newly developed setup for two-colour LII (2C-LII) which provides online monitoring of both the spatial and temporal profile as well as the laser pulse energy. The LII measurements were performed in a one-dimensional premixed sooting ethylene/air flame, and evaluated particle sizes from LII were compared with thermophoretically sampled soot particles analysed using transmission electron microscopy (TEM). The results show that although there is some influence of the spatial laser energy distribution on the evaluated particle sizes both in modelling and experiments, this effect is substantially smaller than the influence of the uncertainties in gas temperature and the thermal accommodation coefficient.},
  author       = {Bladh, Henrik and Johnsson, Jonathan and Bengtsson, Per-Erik},
  issn         = {0946-2171},
  language     = {eng},
  number       = {4},
  pages        = {645--656},
  publisher    = {Springer},
  series       = {Applied Physics B},
  title        = {Influence of spatial laser energy distribution on evaluated soot particle sizes using two-colour laser-induced incandescence in a flat premixed ethylene/air flame},
  url          = {http://dx.doi.org/10.1007/s00340-009-3523-y},
  volume       = {96},
  year         = {2009},
}