Photofragmentation laser-induced fluorescence imaging in premixed flames
(2011) In Combustion and Flame 158(10). p.1908-1919- Abstract
- Two-dimensional measurements of primarily hydroperoxyl radicals (HO2) are, for the first time, demonstrated in flames. The measurements are performed in different Bunsen-type premixed flames (H-2/O-2. CH4/O-2, and CH4/air) using photofragmentation laser-induced fluorescence (PF-LIF). Photofragmentation is done by laser radiation at 266 nm, and the generated OH photofragments are probed through fluorescence induced by a laser tuned to the Q(1)(5) transition at 282.75 nm. The signal due to naturally occurring OH radicals, recorded by having the photolysis laser blocked, is subtracted, providing an image that reflects the concentration of OH fragments generated by photolysis, and hence the presence of primarily HO2, but also smaller... (More)
- Two-dimensional measurements of primarily hydroperoxyl radicals (HO2) are, for the first time, demonstrated in flames. The measurements are performed in different Bunsen-type premixed flames (H-2/O-2. CH4/O-2, and CH4/air) using photofragmentation laser-induced fluorescence (PF-LIF). Photofragmentation is done by laser radiation at 266 nm, and the generated OH photofragments are probed through fluorescence induced by a laser tuned to the Q(1)(5) transition at 282.75 nm. The signal due to naturally occurring OH radicals, recorded by having the photolysis laser blocked, is subtracted, providing an image that reflects the concentration of OH fragments generated by photolysis, and hence the presence of primarily HO2, but also smaller contributions from H2O2 and, for the methane flames, CH3O2. For the methane flames the measured radial profiles of OH photofragments and natural OH agree well with corresponding profiles calculated for laminar, one-dimensional, premixed flames using CHEMKIN-II with the Konnov detailed C/H/N/O reaction mechanism. An interfering signal contribution is observed in the product zone of the methane flames. It is concluded that the major source for the interference is most likely hot CO2, from which 0 atoms are produced by photolysis, and OH is rapidly formed as the O atoms react with H2O and H-2. This conclusion is supported by the fact that the interference is absent for the hydrogen flame, but appears when CO2 is seeded into the flame. Another strong indication is that the Konnov mechanism predicts a similar buildup of OH after photolysis. (C) 2011 The Combustion Institute. Published by Elsevier Inc. All rights reserved. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/2160586
- author
- Johansson, Olof LU ; Bood, Joakim LU ; Li, Bo LU ; Ehn, Andreas LU ; Li, Zhongshan LU ; Sun, Zhiwei LU ; Jonsson, Malin LU ; Konnov, Alexander LU and Aldén, Marcus LU
- organization
- publishing date
- 2011
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Combustion diagnostics, Photofragmentation, Laser-induced fluorescence, Hydrogen peroxide, Hydroperoxyl radical, Methyl peroxy radical
- in
- Combustion and Flame
- volume
- 158
- issue
- 10
- pages
- 1908 - 1919
- publisher
- Elsevier
- external identifiers
-
- wos:000294525200007
- scopus:80052385274
- ISSN
- 0010-2180
- DOI
- 10.1016/j.combustflame.2011.02.021
- language
- English
- LU publication?
- yes
- id
- 47562296-0958-4fbf-8606-d4f3912a1848 (old id 2160586)
- date added to LUP
- 2016-04-01 14:35:39
- date last changed
- 2022-04-14 18:39:26
@article{47562296-0958-4fbf-8606-d4f3912a1848, abstract = {{Two-dimensional measurements of primarily hydroperoxyl radicals (HO2) are, for the first time, demonstrated in flames. The measurements are performed in different Bunsen-type premixed flames (H-2/O-2. CH4/O-2, and CH4/air) using photofragmentation laser-induced fluorescence (PF-LIF). Photofragmentation is done by laser radiation at 266 nm, and the generated OH photofragments are probed through fluorescence induced by a laser tuned to the Q(1)(5) transition at 282.75 nm. The signal due to naturally occurring OH radicals, recorded by having the photolysis laser blocked, is subtracted, providing an image that reflects the concentration of OH fragments generated by photolysis, and hence the presence of primarily HO2, but also smaller contributions from H2O2 and, for the methane flames, CH3O2. For the methane flames the measured radial profiles of OH photofragments and natural OH agree well with corresponding profiles calculated for laminar, one-dimensional, premixed flames using CHEMKIN-II with the Konnov detailed C/H/N/O reaction mechanism. An interfering signal contribution is observed in the product zone of the methane flames. It is concluded that the major source for the interference is most likely hot CO2, from which 0 atoms are produced by photolysis, and OH is rapidly formed as the O atoms react with H2O and H-2. This conclusion is supported by the fact that the interference is absent for the hydrogen flame, but appears when CO2 is seeded into the flame. Another strong indication is that the Konnov mechanism predicts a similar buildup of OH after photolysis. (C) 2011 The Combustion Institute. Published by Elsevier Inc. All rights reserved.}}, author = {{Johansson, Olof and Bood, Joakim and Li, Bo and Ehn, Andreas and Li, Zhongshan and Sun, Zhiwei and Jonsson, Malin and Konnov, Alexander and Aldén, Marcus}}, issn = {{0010-2180}}, keywords = {{Combustion diagnostics; Photofragmentation; Laser-induced fluorescence; Hydrogen peroxide; Hydroperoxyl radical; Methyl peroxy radical}}, language = {{eng}}, number = {{10}}, pages = {{1908--1919}}, publisher = {{Elsevier}}, series = {{Combustion and Flame}}, title = {{Photofragmentation laser-induced fluorescence imaging in premixed flames}}, url = {{http://dx.doi.org/10.1016/j.combustflame.2011.02.021}}, doi = {{10.1016/j.combustflame.2011.02.021}}, volume = {{158}}, year = {{2011}}, }