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Soot Formation in Unstrained Diffusion Flames

Robert, Etienne; Olofsson, Nils-Erik LU ; Bladh, Henrik LU ; Johnsson, Jonathan LU and Bengtsson, Per-Erik LU (2015) In Combustion Science and Technology 187(4). p.577-593
Abstract
The formation of soot particles has been investigated in CH4/O-2 diffusion flames using a unique burner design, which allows the creation of a nearly unstrained planar reaction sheet. Spatially resolved soot volume fractions were obtained using laser-induced incandescence. These soot measurements and the sooting limits were obtained as a function of bulk flow across the flame and mixture strength. Samples were collected using thermophoretic sampling and analyzed using electron microscopy, revealing a broad range of microstructures including particles with unusually large primary diameters and carbon nanotubes. A theoretical model is presented, which confirms that under certain conditions the 1D nature of the flow field of the burner and... (More)
The formation of soot particles has been investigated in CH4/O-2 diffusion flames using a unique burner design, which allows the creation of a nearly unstrained planar reaction sheet. Spatially resolved soot volume fractions were obtained using laser-induced incandescence. These soot measurements and the sooting limits were obtained as a function of bulk flow across the flame and mixture strength. Samples were collected using thermophoretic sampling and analyzed using electron microscopy, revealing a broad range of microstructures including particles with unusually large primary diameters and carbon nanotubes. A theoretical model is presented, which confirms that under certain conditions the 1D nature of the flow field of the burner and the strong adverse temperature gradient on the fuel side of the flame result in the soot particles being held in place by thermophoretic forces and allowed to grow for very long time periods. Some of these so-called super aggregates reached sizes of tens of microns and became visible to the naked eye in the soot layer. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Diffusion flame, Laser-induced incandescence, Soot, Super aggregate, Thermophoresis
in
Combustion Science and Technology
volume
187
issue
4
pages
577 - 593
publisher
Taylor & Francis
external identifiers
  • wos:000348467200005
  • scopus:84961369473
ISSN
1563-521X
DOI
10.1080/00102202.2014.958219
language
English
LU publication?
yes
id
8d7a404d-ca63-4b19-a6fc-2f2b7e349f56 (old id 5194635)
date added to LUP
2015-03-27 13:42:40
date last changed
2017-03-26 03:02:54
@article{8d7a404d-ca63-4b19-a6fc-2f2b7e349f56,
  abstract     = {The formation of soot particles has been investigated in CH4/O-2 diffusion flames using a unique burner design, which allows the creation of a nearly unstrained planar reaction sheet. Spatially resolved soot volume fractions were obtained using laser-induced incandescence. These soot measurements and the sooting limits were obtained as a function of bulk flow across the flame and mixture strength. Samples were collected using thermophoretic sampling and analyzed using electron microscopy, revealing a broad range of microstructures including particles with unusually large primary diameters and carbon nanotubes. A theoretical model is presented, which confirms that under certain conditions the 1D nature of the flow field of the burner and the strong adverse temperature gradient on the fuel side of the flame result in the soot particles being held in place by thermophoretic forces and allowed to grow for very long time periods. Some of these so-called super aggregates reached sizes of tens of microns and became visible to the naked eye in the soot layer.},
  author       = {Robert, Etienne and Olofsson, Nils-Erik and Bladh, Henrik and Johnsson, Jonathan and Bengtsson, Per-Erik},
  issn         = {1563-521X},
  keyword      = {Diffusion flame,Laser-induced incandescence,Soot,Super aggregate,Thermophoresis},
  language     = {eng},
  number       = {4},
  pages        = {577--593},
  publisher    = {Taylor & Francis},
  series       = {Combustion Science and Technology},
  title        = {Soot Formation in Unstrained Diffusion Flames},
  url          = {http://dx.doi.org/10.1080/00102202.2014.958219},
  volume       = {187},
  year         = {2015},
}