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Planar laser-induced photofragmentation fluorescence for quantitative ammonia imaging in combustion environments

Weng, Wubin LU ; Brackmann, Christian LU ; Aldén, Marcus LU and Li, Zhongshan LU (2022) In Combustion and Flame 235.
Abstract

Ammonia is regarded as a potential carbon-free alternative fuel. To have a better understanding of its combustion characteristics, development of feasible techniques for ammonia detection in combustion environments is essential. In the present work, planar laser-induced photofragmentation fluorescence (LIPF) was developed for quantitative measurements of ammonia in hot gas flows. A 193 nm ArF excimer laser was used to photo-dissociate ammonia. As a fragment, NH* radicals were generated, and the fluorescence at 336 nm was used for ammonia detection. Quantitative calibration of the LIPF signal was performed in hot flows either from laminar flames or an electric heating-pipe with a known amount of ammonia and temperature. Ultraviolet... (More)

Ammonia is regarded as a potential carbon-free alternative fuel. To have a better understanding of its combustion characteristics, development of feasible techniques for ammonia detection in combustion environments is essential. In the present work, planar laser-induced photofragmentation fluorescence (LIPF) was developed for quantitative measurements of ammonia in hot gas flows. A 193 nm ArF excimer laser was used to photo-dissociate ammonia. As a fragment, NH* radicals were generated, and the fluorescence at 336 nm was used for ammonia detection. Quantitative calibration of the LIPF signal was performed in hot flows either from laminar flames or an electric heating-pipe with a known amount of ammonia and temperature. Ultraviolet absorption was used to obtain accurate concentrations of ammonia in the hot flows from laminar flames. The single-shot detection limit of the LIPF technique was estimated to be ∼50 ppm and ∼130 ppm in hot flue gas at 1140 and 1750 K, respectively, and ∼0.2 ppm in a room-temperature nitrogen flow. The technique was applied to detect the slip of ammonia in a premixed laminar ammonia-air flame with a fuel-air equivalence ratio of 1.2. Over 5000 ppm unburned ammonia was detected in the post-flame region and measurements showed good agreement with predictions of a chemical model.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ammonia, Combustion environment, Laser-induced photofragmentation fluorescence, Premixed laminar flame, Quantitative imaging, UV laser spectroscopy
in
Combustion and Flame
volume
235
article number
111687
publisher
Elsevier
external identifiers
  • scopus:85114951173
ISSN
0010-2180
DOI
10.1016/j.combustflame.2021.111687
language
English
LU publication?
yes
id
2b6fc6f5-b9e9-4b4c-b630-f558d66b733e
date added to LUP
2021-10-11 14:24:19
date last changed
2022-04-19 08:49:44
@article{2b6fc6f5-b9e9-4b4c-b630-f558d66b733e,
  abstract     = {{<p>Ammonia is regarded as a potential carbon-free alternative fuel. To have a better understanding of its combustion characteristics, development of feasible techniques for ammonia detection in combustion environments is essential. In the present work, planar laser-induced photofragmentation fluorescence (LIPF) was developed for quantitative measurements of ammonia in hot gas flows. A 193 nm ArF excimer laser was used to photo-dissociate ammonia. As a fragment, NH* radicals were generated, and the fluorescence at 336 nm was used for ammonia detection. Quantitative calibration of the LIPF signal was performed in hot flows either from laminar flames or an electric heating-pipe with a known amount of ammonia and temperature. Ultraviolet absorption was used to obtain accurate concentrations of ammonia in the hot flows from laminar flames. The single-shot detection limit of the LIPF technique was estimated to be ∼50 ppm and ∼130 ppm in hot flue gas at 1140 and 1750 K, respectively, and ∼0.2 ppm in a room-temperature nitrogen flow. The technique was applied to detect the slip of ammonia in a premixed laminar ammonia-air flame with a fuel-air equivalence ratio of 1.2. Over 5000 ppm unburned ammonia was detected in the post-flame region and measurements showed good agreement with predictions of a chemical model.</p>}},
  author       = {{Weng, Wubin and Brackmann, Christian and Aldén, Marcus and Li, Zhongshan}},
  issn         = {{0010-2180}},
  keywords     = {{Ammonia; Combustion environment; Laser-induced photofragmentation fluorescence; Premixed laminar flame; Quantitative imaging; UV laser spectroscopy}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Combustion and Flame}},
  title        = {{Planar laser-induced photofragmentation fluorescence for quantitative ammonia imaging in combustion environments}},
  url          = {{http://dx.doi.org/10.1016/j.combustflame.2021.111687}},
  doi          = {{10.1016/j.combustflame.2021.111687}},
  volume       = {{235}},
  year         = {{2022}},
}