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Strategy for single-shot CH3 imaging in premixed methane/air flames using photofragmentation laser-induced fluorescence

Li, Bo LU ; Zhang, Dayuan; Yao, Mingfa and Li, Zhongshan LU (2017) In Proceedings of the Combustion Institute2000-01-01+01:00 p.4487-4495
Abstract

Single-shot imaging of methyl radical (CH3) in premixed methane/air flames is demonstrated using photofragmentation laser-induced fluorescence (PF-LIF) technique. A pump-probe strategy was adopted with the pump laser at 212.8 nm photolyzing CH3, and with the probe laser at 426.8 nm detecting the photolyzed CH (X 2Π) fragments. Spatially resolved spectrograph of the PF-LIF signal from a stable laminar flame was recorded across the reaction zone to investigate potential interferences. The results indicate that the single-photon channel, CH3 + 212.8 nm → CH (X 2Π) + H2, dominates the photofragmentation process. The CH2 radical was excluded from being an... (More)

Single-shot imaging of methyl radical (CH3) in premixed methane/air flames is demonstrated using photofragmentation laser-induced fluorescence (PF-LIF) technique. A pump-probe strategy was adopted with the pump laser at 212.8 nm photolyzing CH3, and with the probe laser at 426.8 nm detecting the photolyzed CH (X 2Π) fragments. Spatially resolved spectrograph of the PF-LIF signal from a stable laminar flame was recorded across the reaction zone to investigate potential interferences. The results indicate that the single-photon channel, CH3 + 212.8 nm → CH (X 2Π) + H2, dominates the photofragmentation process. The CH2 radical was excluded from being an interfering precursor of the CH (X 2Π) fragments owing to its relatively low concentration and small absorption cross section. Naturally present CH in the flame was identified as the main interference, but was conservatively estimated to account for only less than 4% of the total PF-LIF signal. Signal-to-noise ratio of around 10 was realized for single-shot imaging of natural CH3 in turbulent jet flames.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CH, Laser-induced fluorescence, Photofragmentation, Single-shot imaging, Turbulent methane/air flames
in
Proceedings of the Combustion Institute2000-01-01+01:00
pages
4487 - 4495
publisher
Elsevier
external identifiers
  • scopus:85008683497
  • wos:000393412600130
ISSN
1540-7489
DOI
10.1016/j.proci.2016.07.082
language
English
LU publication?
yes
id
8c6d59f9-459d-4611-8ed2-75c3b0b6cf5d
date added to LUP
2017-02-17 12:35:21
date last changed
2018-01-07 11:50:49
@article{8c6d59f9-459d-4611-8ed2-75c3b0b6cf5d,
  abstract     = {<p>Single-shot imaging of methyl radical (CH<sub>3</sub>) in premixed methane/air flames is demonstrated using photofragmentation laser-induced fluorescence (PF-LIF) technique. A pump-probe strategy was adopted with the pump laser at 212.8 nm photolyzing CH<sub>3</sub>, and with the probe laser at 426.8 nm detecting the photolyzed CH (X <sup>2</sup>Π) fragments. Spatially resolved spectrograph of the PF-LIF signal from a stable laminar flame was recorded across the reaction zone to investigate potential interferences. The results indicate that the single-photon channel, CH<sub>3</sub> + 212.8 nm → CH (X <sup>2</sup>Π) + H<sub>2</sub>, dominates the photofragmentation process. The CH<sub>2</sub> radical was excluded from being an interfering precursor of the CH (X <sup>2</sup>Π) fragments owing to its relatively low concentration and small absorption cross section. Naturally present CH in the flame was identified as the main interference, but was conservatively estimated to account for only less than 4% of the total PF-LIF signal. Signal-to-noise ratio of around 10 was realized for single-shot imaging of natural CH<sub>3</sub> in turbulent jet flames.</p>},
  author       = {Li, Bo and Zhang, Dayuan and Yao, Mingfa and Li, Zhongshan},
  issn         = {1540-7489},
  keyword      = {CH,Laser-induced fluorescence,Photofragmentation,Single-shot imaging,Turbulent methane/air flames},
  language     = {eng},
  pages        = {4487--4495},
  publisher    = {Elsevier},
  series       = {Proceedings of the Combustion Institute2000-01-01+01:00},
  title        = {Strategy for single-shot CH<sub>3</sub> imaging in premixed methane/air flames using photofragmentation laser-induced fluorescence},
  url          = {http://dx.doi.org/10.1016/j.proci.2016.07.082},
  year         = {2017},
}