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Diesel flame lift-off stabilization in the presence of laser-ignition: a numerical study

Gong, Cheng LU ; Jangi, Mehdi LU and Bai, Xue-Song LU (2015) In Combustion Theory and Modelling 19(6). p.696-713
Abstract
Diesel flame lift-off and stabilization in the presence of laser-ignition were numerically investigated with the method of Eulerian stochastic fields. The aim was to scrutinise the interaction between the lifted diesel flame and an ignition kernel upstream of the lifted flame. The numerical simulation was carried out in a constant-volume combustion vessel with n-heptane as fuel. The process was studied previously in an experiment employing Diesel #2 as the fuel in the same combustion vessel. In the experiment a lifted flame was first established at a position downstream of the nozzle. An ignition kernel was then initiated using a high-energy pulse laser at a position upstream of the natural lift-off position of the diesel flame. The... (More)
Diesel flame lift-off and stabilization in the presence of laser-ignition were numerically investigated with the method of Eulerian stochastic fields. The aim was to scrutinise the interaction between the lifted diesel flame and an ignition kernel upstream of the lifted flame. The numerical simulation was carried out in a constant-volume combustion vessel with n-heptane as fuel. The process was studied previously in an experiment employing Diesel #2 as the fuel in the same combustion vessel. In the experiment a lifted flame was first established at a position downstream of the nozzle. An ignition kernel was then initiated using a high-energy pulse laser at a position upstream of the natural lift-off position of the diesel flame. The laser-ignition kernel was modelled using a high-temperature (approximate to 2000K) hot spot. In both experiment and simulations the upstream front of the ignition kernel was shown to remain around the initial laser ignition site for a substantially long period of time, while the downstream front of the ignition kernel propagates rapidly towards the natural lift-off position downstream of the laser ignition site. The lift-off position oscillated before the final stabilization at the natural lift-off position. The structures and the propagation speed of the reaction fronts in the laser-ignition kernel and the main flame were analysed. Two different stabilization mechanisms, the auto-ignition mechanism and the flame propagation mechanism, were identified for the naturally lifted flame and the laser-induced reaction front, respectively. A mechanism was proposed to explain the oscillation of the lift-off position. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
diesel combustion, flame stabilization, auto-ignition, laser ignition, Eulerian stochastic fields method
in
Combustion Theory and Modelling
volume
19
issue
6
pages
696 - 713
publisher
Taylor & Francis
external identifiers
  • wos:000366248600002
  • scopus:84949533795
ISSN
1364-7830
DOI
10.1080/13647830.2015.1077997
language
English
LU publication?
yes
id
12bb8e89-5eca-4409-81a1-8ae0ee21cf7f (old id 8556621)
date added to LUP
2016-01-28 09:33:24
date last changed
2017-11-05 03:26:50
@article{12bb8e89-5eca-4409-81a1-8ae0ee21cf7f,
  abstract     = {Diesel flame lift-off and stabilization in the presence of laser-ignition were numerically investigated with the method of Eulerian stochastic fields. The aim was to scrutinise the interaction between the lifted diesel flame and an ignition kernel upstream of the lifted flame. The numerical simulation was carried out in a constant-volume combustion vessel with n-heptane as fuel. The process was studied previously in an experiment employing Diesel #2 as the fuel in the same combustion vessel. In the experiment a lifted flame was first established at a position downstream of the nozzle. An ignition kernel was then initiated using a high-energy pulse laser at a position upstream of the natural lift-off position of the diesel flame. The laser-ignition kernel was modelled using a high-temperature (approximate to 2000K) hot spot. In both experiment and simulations the upstream front of the ignition kernel was shown to remain around the initial laser ignition site for a substantially long period of time, while the downstream front of the ignition kernel propagates rapidly towards the natural lift-off position downstream of the laser ignition site. The lift-off position oscillated before the final stabilization at the natural lift-off position. The structures and the propagation speed of the reaction fronts in the laser-ignition kernel and the main flame were analysed. Two different stabilization mechanisms, the auto-ignition mechanism and the flame propagation mechanism, were identified for the naturally lifted flame and the laser-induced reaction front, respectively. A mechanism was proposed to explain the oscillation of the lift-off position.},
  author       = {Gong, Cheng and Jangi, Mehdi and Bai, Xue-Song},
  issn         = {1364-7830},
  keyword      = {diesel combustion,flame stabilization,auto-ignition,laser ignition,Eulerian stochastic fields method},
  language     = {eng},
  number       = {6},
  pages        = {696--713},
  publisher    = {Taylor & Francis},
  series       = {Combustion Theory and Modelling},
  title        = {Diesel flame lift-off stabilization in the presence of laser-ignition: a numerical study},
  url          = {http://dx.doi.org/10.1080/13647830.2015.1077997},
  volume       = {19},
  year         = {2015},
}