SAFT Regimes and Laminar Burning Velocities : A Comparative Study of NH3+ N2+ O2and CH4+ N2+ O2Flames
(2023) In Energy and Fuels 37(11). p.7958-7972- Abstract
Super adiabatic flame temperature (SAFT) is a distinctive phenomenon in the adiabatic flame where the local maximum temperature exceeds the adiabatic flame temperature. The flame temperatures exhibiting the extent of SAFT are difficult to measure with low uncertainties in experiments, while the laminar burning velocity also represents global flame features, thus could possibly be related to the SAFT. The present study investigated the SAFT regimes, laminar burning velocities (SL), and their relationships for the CH4+ O2+ N2and NH3+ O2+ N2flames over large equivalence (φ) and oxygen ratio (xO2) ranges. The laminar burning velocities were... (More)
Super adiabatic flame temperature (SAFT) is a distinctive phenomenon in the adiabatic flame where the local maximum temperature exceeds the adiabatic flame temperature. The flame temperatures exhibiting the extent of SAFT are difficult to measure with low uncertainties in experiments, while the laminar burning velocity also represents global flame features, thus could possibly be related to the SAFT. The present study investigated the SAFT regimes, laminar burning velocities (SL), and their relationships for the CH4+ O2+ N2and NH3+ O2+ N2flames over large equivalence (φ) and oxygen ratio (xO2) ranges. The laminar burning velocities were experimentally measured using the heat flux method at φ = 1.4-1.8 and xO2= 0.22-0.44, where some conditions have never been reported before in the literature. Comparisons were made with simulated SLresults using five CH4mechanisms and five NH3mechanisms, and none of them well reproduce all of the experimental data. From the simulation results, three CH4SAFT regimes (I, II, and III) and two NH3SAFT regimes (I and II) have been identified, among which regime III for CH4and regime II for NH3were found for the first time. The kinetic origins of these regimes were discussed, and different flame features regarding the flame temperature and dominant species were clarified. The relationship between the SAFT extent and the laminar burning velocity is revealed by equation derivation based on the classical flame theories, proving that a mechanism reproducing well the SLand its temperature dependence can at the same time yield accurate predictions of the SAFT. The present study also provided the most sensitive reactions in the SAFT predictions accompanied by the rate constant uncertainties, which can be helpful for further mechanism development since none of the mechanisms reproduces well the present SLexperimental data, let alone the SAFT extent.
(Less)
- author
- Han, Xinlu LU ; Wang, Zhihua ; Lin, Riyi and Konnov, Alexander A. LU
- organization
- publishing date
- 2023-06-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Energy and Fuels
- volume
- 37
- issue
- 11
- pages
- 15 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:85160687627
- ISSN
- 0887-0624
- DOI
- 10.1021/acs.energyfuels.3c00943
- language
- English
- LU publication?
- yes
- id
- ef1ad039-329e-4b2c-82b2-fdb59c896828
- date added to LUP
- 2023-08-29 15:45:20
- date last changed
- 2023-11-08 10:19:59
@article{ef1ad039-329e-4b2c-82b2-fdb59c896828,
abstract = {{<p>Super adiabatic flame temperature (SAFT) is a distinctive phenomenon in the adiabatic flame where the local maximum temperature exceeds the adiabatic flame temperature. The flame temperatures exhibiting the extent of SAFT are difficult to measure with low uncertainties in experiments, while the laminar burning velocity also represents global flame features, thus could possibly be related to the SAFT. The present study investigated the SAFT regimes, laminar burning velocities (S<sub>L</sub>), and their relationships for the CH<sub>4</sub>+ O<sub>2</sub>+ N<sub>2</sub>and NH<sub>3</sub>+ O<sub>2</sub>+ N<sub>2</sub>flames over large equivalence (φ) and oxygen ratio (x<sub>O<sub>2</sub></sub>) ranges. The laminar burning velocities were experimentally measured using the heat flux method at φ = 1.4-1.8 and x<sub>O<sub>2</sub></sub>= 0.22-0.44, where some conditions have never been reported before in the literature. Comparisons were made with simulated S<sub>L</sub>results using five CH<sub>4</sub>mechanisms and five NH<sub>3</sub>mechanisms, and none of them well reproduce all of the experimental data. From the simulation results, three CH<sub>4</sub>SAFT regimes (I, II, and III) and two NH<sub>3</sub>SAFT regimes (I and II) have been identified, among which regime III for CH<sub>4</sub>and regime II for NH<sub>3</sub>were found for the first time. The kinetic origins of these regimes were discussed, and different flame features regarding the flame temperature and dominant species were clarified. The relationship between the SAFT extent and the laminar burning velocity is revealed by equation derivation based on the classical flame theories, proving that a mechanism reproducing well the S<sub>L</sub>and its temperature dependence can at the same time yield accurate predictions of the SAFT. The present study also provided the most sensitive reactions in the SAFT predictions accompanied by the rate constant uncertainties, which can be helpful for further mechanism development since none of the mechanisms reproduces well the present S<sub>L</sub>experimental data, let alone the SAFT extent.</p>}},
author = {{Han, Xinlu and Wang, Zhihua and Lin, Riyi and Konnov, Alexander A.}},
issn = {{0887-0624}},
language = {{eng}},
month = {{06}},
number = {{11}},
pages = {{7958--7972}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Energy and Fuels}},
title = {{SAFT Regimes and Laminar Burning Velocities : A Comparative Study of NH<sub>3</sub>+ N<sub>2</sub>+ O<sub>2</sub>and CH<sub>4</sub>+ N<sub>2</sub>+ O<sub>2</sub>Flames}},
url = {{http://dx.doi.org/10.1021/acs.energyfuels.3c00943}},
doi = {{10.1021/acs.energyfuels.3c00943}},
volume = {{37}},
year = {{2023}},
}