Direct numerical simulations of auto-igniting mixing layers in ammonia and ammonia-hydrogen combustion under engine-relevant conditions
Direct numerical simulations of auto-igniting mixing layers in ammonia and ammonia-hydrogen combustion under engine-relevant conditions
This study investigated auto-ignition characteristics of ammonia-air and ammonia-hydrogen-air laminar and turbulent mixing layers by means of direct numerical simulations (DNS) under elevated pressure conditions. The results show that elevated pressure and hydrogen addition accelerate the auto-ignition process, reducing the auto-ignition delay time. Analysis of the heat release rate revealed that the first peak of the heat release rate corresponds to the increment of appearance in temperature (induction stage) and the second peak of the heat release rate corresponds to the steady maximum temperature regime (thermal runaway stage). The results found that both induction and thermal runaway stages are affected by turbulence for pure ammonia-air mixing layers, while only the thermal runaway stage is affected by turbulence for ammonia-hydrogen-air mixing layers. The auto-ignition occurs along the most reactive mixture fraction with lower scalar dissipation rate, being further reduced by elevated pressure and hydrogen addition. Three radicals (NH2, OH, HNO) distinguish the entire auto-ignition process very well for all cases.
Ammon-Hydrogen-Air Mixing Layers, Auto-ignition, Direct Numerical Simulation,, Elevated Pressure, High Turbulence
38055-38074
Yang, W
270868b4-d27b-4492-ab19-c35a94af5286
Ranga Dinesh, K.K.J
6454b22c-f505-40f9-8ad4-a1168e8f87cd
Luo, K.H
5d9876df-9f20-4b96-a2f3-02ecdfb06fb7
Thevenin, D
10e800c9-7dfa-414e-be18-2b27cd868c2c
1 November 2022
Yang, W
270868b4-d27b-4492-ab19-c35a94af5286
Ranga Dinesh, K.K.J
6454b22c-f505-40f9-8ad4-a1168e8f87cd
Luo, K.H
5d9876df-9f20-4b96-a2f3-02ecdfb06fb7
Thevenin, D
10e800c9-7dfa-414e-be18-2b27cd868c2c
Yang, W, Ranga Dinesh, K.K.J, Luo, K.H and Thevenin, D
(2022)
Direct numerical simulations of auto-igniting mixing layers in ammonia and ammonia-hydrogen combustion under engine-relevant conditions.
International Journal of Hydrogen Energy, 47 (89), , [volume 47, issue 89].
(doi:10.1016/j.ijhydene.2022.08.290).
Abstract
This study investigated auto-ignition characteristics of ammonia-air and ammonia-hydrogen-air laminar and turbulent mixing layers by means of direct numerical simulations (DNS) under elevated pressure conditions. The results show that elevated pressure and hydrogen addition accelerate the auto-ignition process, reducing the auto-ignition delay time. Analysis of the heat release rate revealed that the first peak of the heat release rate corresponds to the increment of appearance in temperature (induction stage) and the second peak of the heat release rate corresponds to the steady maximum temperature regime (thermal runaway stage). The results found that both induction and thermal runaway stages are affected by turbulence for pure ammonia-air mixing layers, while only the thermal runaway stage is affected by turbulence for ammonia-hydrogen-air mixing layers. The auto-ignition occurs along the most reactive mixture fraction with lower scalar dissipation rate, being further reduced by elevated pressure and hydrogen addition. Three radicals (NH2, OH, HNO) distinguish the entire auto-ignition process very well for all cases.
Text
Yang-et-al-IJHE-Final-Accepted-Version
- Accepted Manuscript
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1-s2.0-S0360319922040071-main
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More information
Accepted/In Press date: 2022
e-pub ahead of print date: 22 September 2022
Published date: 1 November 2022
Additional Information:
Funding Information:
K. H. Luo gratefully acknowledges funding for the research and supercomputing time on ARCHER2 supported by the UK Engineering and Physical Sciences Research Council under the project “ UK Consortium on Mesoscale Engineering Sciences (UKCOMES) ” (Grant No. EP/R029598/1 ).
Publisher Copyright:
© 2022
Keywords:
Ammon-Hydrogen-Air Mixing Layers, Auto-ignition, Direct Numerical Simulation,, Elevated Pressure, High Turbulence
Identifiers
Local EPrints ID: 471137
URI: http://eprints.soton.ac.uk/id/eprint/471137
ISSN: 0360-3199
PURE UUID: b6cb72c7-f01a-4b27-a47e-e153a417803f
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Date deposited: 27 Oct 2022 16:49
Last modified: 17 Mar 2024 07:32
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Contributors
Author:
W Yang
Author:
K.H Luo
Author:
D Thevenin
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