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Diesel fuel jet lift-off stabilization in the presence of laser-induced plasma ignition

Pickett, Lyle M.; Kook, Sanghoon; Persson, Helena LU and Andersson, Öivind LU (2009) In Proceedings of the Combustion Institute2000-01-01+01:00 32. p.2793-2800
Abstract
The mechanisms affecting lift-off stabilization at diesel conditions were investigated by laser-igniting a diesel fuel jet upstream of its natural lift-off position. Single-nozzle fuel sprays penetrating into all optically accessible constant-volume chamber were ignited using laser-induced plasma formation both prior to natural autoignition or after a quasi-steady lift-off length was established. Fuel sprays ignited readily, with reaction kernels growing ill connected regions. After laser-ignition, the lift-off persists upstream of the natural lift-off position for a Substantial period of time indicating that upstream ignition has a strong influence on lift-off stabilization. While not discounting the role of flame propagation downstream... (More)
The mechanisms affecting lift-off stabilization at diesel conditions were investigated by laser-igniting a diesel fuel jet upstream of its natural lift-off position. Single-nozzle fuel sprays penetrating into all optically accessible constant-volume chamber were ignited using laser-induced plasma formation both prior to natural autoignition or after a quasi-steady lift-off length was established. Fuel sprays ignited readily, with reaction kernels growing ill connected regions. After laser-ignition, the lift-off persists upstream of the natural lift-off position for a Substantial period of time indicating that upstream ignition has a strong influence on lift-off stabilization. While not discounting the role of flame propagation downstream of the ignition event, these results show that upstream ignition sites call start a chain of events that effectively controls lift-off. Lift-off eventually returns to its natural position, but only after injection times that are too long for practical engines. The time of return to the natural position depends upon the relative distance of the laser-ignition site to the natural lift-off length. A theory for fuel jet lift-off stabilization based oil flame propagation into pure fuel-ambient reactant streams fails to predict the long upstream stabilization away from the natural lift-off length because turbulent velocities are higher ill upstream regions of the fuel jet. Likewise, upstream lift-off stabilization by autoignition Of pure reactants (no mixing with combustion products) fails because of cooler temperatures and shorter residence times. A potential mechanism explaining the transient lift-off response to laser-ignition is offered based on turbulent mixing with high-temperature combustion products found at the jet edges. Published by Elsevier Inc. on behalf of The Combustion Institute. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Plasma ignition, Diesel combustion, Lifted flames, Soot
in
Proceedings of the Combustion Institute2000-01-01+01:00
volume
32
pages
2793 - 2800
publisher
Elsevier
external identifiers
  • wos:000264756900138
  • scopus:67649277671
ISSN
1540-7489
DOI
10.1016/j.proci.2008.06.082
language
English
LU publication?
yes
id
e5b01ed8-6f6c-4449-a7c8-ca333cf9e5e6 (old id 1400918)
date added to LUP
2009-06-12 10:12:23
date last changed
2017-08-20 03:45:57
@article{e5b01ed8-6f6c-4449-a7c8-ca333cf9e5e6,
  abstract     = {The mechanisms affecting lift-off stabilization at diesel conditions were investigated by laser-igniting a diesel fuel jet upstream of its natural lift-off position. Single-nozzle fuel sprays penetrating into all optically accessible constant-volume chamber were ignited using laser-induced plasma formation both prior to natural autoignition or after a quasi-steady lift-off length was established. Fuel sprays ignited readily, with reaction kernels growing ill connected regions. After laser-ignition, the lift-off persists upstream of the natural lift-off position for a Substantial period of time indicating that upstream ignition has a strong influence on lift-off stabilization. While not discounting the role of flame propagation downstream of the ignition event, these results show that upstream ignition sites call start a chain of events that effectively controls lift-off. Lift-off eventually returns to its natural position, but only after injection times that are too long for practical engines. The time of return to the natural position depends upon the relative distance of the laser-ignition site to the natural lift-off length. A theory for fuel jet lift-off stabilization based oil flame propagation into pure fuel-ambient reactant streams fails to predict the long upstream stabilization away from the natural lift-off length because turbulent velocities are higher ill upstream regions of the fuel jet. Likewise, upstream lift-off stabilization by autoignition Of pure reactants (no mixing with combustion products) fails because of cooler temperatures and shorter residence times. A potential mechanism explaining the transient lift-off response to laser-ignition is offered based on turbulent mixing with high-temperature combustion products found at the jet edges. Published by Elsevier Inc. on behalf of The Combustion Institute.},
  author       = {Pickett, Lyle M. and Kook, Sanghoon and Persson, Helena and Andersson, Öivind},
  issn         = {1540-7489},
  keyword      = {Plasma ignition,Diesel combustion,Lifted flames,Soot},
  language     = {eng},
  pages        = {2793--2800},
  publisher    = {Elsevier},
  series       = {Proceedings of the Combustion Institute2000-01-01+01:00},
  title        = {Diesel fuel jet lift-off stabilization in the presence of laser-induced plasma ignition},
  url          = {http://dx.doi.org/10.1016/j.proci.2008.06.082},
  volume       = {32},
  year         = {2009},
}