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Evolution of properties for aging soot in premixed flat flames studied by laser-induced incandescence and elastic light scattering

Olofsson, Nils-Erik LU ; Simonsson, Johan LU ; Török, Sandra LU ; Bladh, Henrik LU and Bengtsson, Per-Erik LU (2015) In Applied Physics B 119(4). p.669-683
Abstract
A detailed study has been made of soot growth in two premixed flat ethylene/air flames, at I broken vertical bar = 2.1 and I broken vertical bar = 2.3, where focus has been on following the change in optical properties from nascent to more mature soot, and the importance of these properties for laser-induced incandescence (LII). A combination of two-color LII (2C-LII) and elastic light scattering was utilized for studies of soot absorption and sublimation for a range of laser fluences in a pump-probe experiment, and the experimental results were compared with LII model predictions. Both flames show similar trends, indicating that the soot becomes less transparent during the growth process until some level of maturity is reached at higher... (More)
A detailed study has been made of soot growth in two premixed flat ethylene/air flames, at I broken vertical bar = 2.1 and I broken vertical bar = 2.3, where focus has been on following the change in optical properties from nascent to more mature soot, and the importance of these properties for laser-induced incandescence (LII). A combination of two-color LII (2C-LII) and elastic light scattering was utilized for studies of soot absorption and sublimation for a range of laser fluences in a pump-probe experiment, and the experimental results were compared with LII model predictions. Both flames show similar trends, indicating that the soot becomes less transparent during the growth process until some level of maturity is reached at higher flame heights, where the measured properties reach almost constant values. A sublimation fluence threshold of similar to 0.14 J/cm(2) (at 1064 nm for a flame temperature around 1700 K) was evaluated for mature soot, corresponding to a sublimation temperature of similar to 3400 K. Soot peak temperatures from 2C-LII were evaluated both using a constant E(m) and a wavelength dependence for E(m) extracted from extinction measurements, leading to a discussion on how the sublimation temperature relates to the maturity of soot. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Physics B
volume
119
issue
4
pages
669 - 683
publisher
Springer
external identifiers
  • wos:000354703800008
  • scopus:84929702757
ISSN
0946-2171
DOI
10.1007/s00340-015-6067-3
language
English
LU publication?
yes
id
8849f3b2-9ec9-4559-b211-5c9500bd72a0 (old id 7422746)
date added to LUP
2015-06-26 11:03:33
date last changed
2017-11-19 03:20:04
@article{8849f3b2-9ec9-4559-b211-5c9500bd72a0,
  abstract     = {A detailed study has been made of soot growth in two premixed flat ethylene/air flames, at I broken vertical bar = 2.1 and I broken vertical bar = 2.3, where focus has been on following the change in optical properties from nascent to more mature soot, and the importance of these properties for laser-induced incandescence (LII). A combination of two-color LII (2C-LII) and elastic light scattering was utilized for studies of soot absorption and sublimation for a range of laser fluences in a pump-probe experiment, and the experimental results were compared with LII model predictions. Both flames show similar trends, indicating that the soot becomes less transparent during the growth process until some level of maturity is reached at higher flame heights, where the measured properties reach almost constant values. A sublimation fluence threshold of similar to 0.14 J/cm(2) (at 1064 nm for a flame temperature around 1700 K) was evaluated for mature soot, corresponding to a sublimation temperature of similar to 3400 K. Soot peak temperatures from 2C-LII were evaluated both using a constant E(m) and a wavelength dependence for E(m) extracted from extinction measurements, leading to a discussion on how the sublimation temperature relates to the maturity of soot.},
  author       = {Olofsson, Nils-Erik and Simonsson, Johan and Török, Sandra and Bladh, Henrik and Bengtsson, Per-Erik},
  issn         = {0946-2171},
  language     = {eng},
  number       = {4},
  pages        = {669--683},
  publisher    = {Springer},
  series       = {Applied Physics B},
  title        = {Evolution of properties for aging soot in premixed flat flames studied by laser-induced incandescence and elastic light scattering},
  url          = {http://dx.doi.org/10.1007/s00340-015-6067-3},
  volume       = {119},
  year         = {2015},
}