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Ignition processes and modes excited by laser-induced plasma in a cavity-based supersonic combustor

Cai, Zun; Zhu, Jiajian LU ; Sun, Mingbo; Wang, Zhenguo and Bai, Xue Song LU (2018) In Applied Energy 228. p.1777-1782
Abstract

The ignition processes in an ethylene-fueled supersonic combustor excited by laser-induced plasma (LIP) were investigated experimentally under the condition of inflow Ma number of 2.92. The LIP excitation was implemented near the center floor of a flameholding cavity. Optical measurements, including simultaneous CH/OH chemiluminescence imaging and Schlieren photography, were used to investigate the ignition processes. It is found that the CH and OH initiated by the LIP are mainly in the region between the cavity front wall and the LIP excitation site. The CH and OH are quenched rapidly, in particular at a low fueling rate. After a short delay, the distribution of... (More)

The ignition processes in an ethylene-fueled supersonic combustor excited by laser-induced plasma (LIP) were investigated experimentally under the condition of inflow Ma number of 2.92. The LIP excitation was implemented near the center floor of a flameholding cavity. Optical measurements, including simultaneous CH/OH chemiluminescence imaging and Schlieren photography, were used to investigate the ignition processes. It is found that the CH and OH initiated by the LIP are mainly in the region between the cavity front wall and the LIP excitation site. The CH and OH are quenched rapidly, in particular at a low fueling rate. After a short delay, the distribution of CH and OH appears in the region between the rear wall of the cavity and the LIP excitation site, showing the onset of ignition therein. A stable flame was established in the shear layer between the downstream part of the cavity and the outer supersonic flow. It is concluded that the ignition processes excited by the LIP can be divided into a LIP initiation regime and a transient ignition reaction regime. Both the fueling rate and the LIP energy significantly affect the cavity ignition processes. Increasing the fueling rate or the laser energy can shorten the ignition processes in the cavity. A weak ignition mode and an intense ignition mode are postulated to explain the combustion behavior of the ignition processes in the cavity-based supersonic combustor.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CH chemiluminescence, Equivalence ratio, Ignition processes, Laser-induced plasma, OH chemiluminescence
in
Applied Energy
volume
228
pages
6 pages
publisher
Elsevier
external identifiers
  • scopus:85050100822
ISSN
0306-2619
DOI
10.1016/j.apenergy.2018.07.079
language
English
LU publication?
yes
id
1d7f509c-535e-4e93-add1-91e1926d5503
date added to LUP
2018-07-31 12:26:01
date last changed
2019-10-15 06:42:24
@article{1d7f509c-535e-4e93-add1-91e1926d5503,
  abstract     = {<p>The ignition processes in an ethylene-fueled supersonic combustor excited by laser-induced plasma (LIP) were investigated experimentally under the condition of inflow Ma number of 2.92. The LIP excitation was implemented near the center floor of a flameholding cavity. Optical measurements, including simultaneous CH<sup>∗</sup>/OH<sup>∗</sup> chemiluminescence imaging and Schlieren photography, were used to investigate the ignition processes. It is found that the CH<sup>∗</sup> and OH<sup>∗</sup> initiated by the LIP are mainly in the region between the cavity front wall and the LIP excitation site. The CH<sup>∗</sup> and OH<sup>∗</sup> are quenched rapidly, in particular at a low fueling rate. After a short delay, the distribution of CH<sup>∗</sup> and OH<sup>∗</sup> appears in the region between the rear wall of the cavity and the LIP excitation site, showing the onset of ignition therein. A stable flame was established in the shear layer between the downstream part of the cavity and the outer supersonic flow. It is concluded that the ignition processes excited by the LIP can be divided into a LIP initiation regime and a transient ignition reaction regime. Both the fueling rate and the LIP energy significantly affect the cavity ignition processes. Increasing the fueling rate or the laser energy can shorten the ignition processes in the cavity. A weak ignition mode and an intense ignition mode are postulated to explain the combustion behavior of the ignition processes in the cavity-based supersonic combustor.</p>},
  author       = {Cai, Zun and Zhu, Jiajian and Sun, Mingbo and Wang, Zhenguo and Bai, Xue Song},
  issn         = {0306-2619},
  keyword      = {CH chemiluminescence,Equivalence ratio,Ignition processes,Laser-induced plasma,OH chemiluminescence},
  language     = {eng},
  month        = {10},
  pages        = {1777--1782},
  publisher    = {Elsevier},
  series       = {Applied Energy},
  title        = {Ignition processes and modes excited by laser-induced plasma in a cavity-based supersonic combustor},
  url          = {http://dx.doi.org/10.1016/j.apenergy.2018.07.079},
  volume       = {228},
  year         = {2018},
}