Direct numerical simulation of turbulent premixed ammonia and ammonia-hydrogen combustion under engine-relevant conditions
Direct numerical simulation of turbulent premixed ammonia and ammonia-hydrogen combustion under engine-relevant conditions
The combustion characteristics of ammonia and ammonia-hydrogen fuel blends under spark-ignited turbulent premixed engine-relevant conditions were investigated by means of direct numerical simulation and detailed chemistry. Several test cases were investigated for an outwardly expanding turbulent premixed flame configuration covering pure ammonia and ammonia-hydrogen fuel blends with 10% and 15% hydrogen content by volume for different equivalence ratio values of 0.9, 1.0 and 1.1. The results showed that the fuel-lean flames exhibit strong wrinkled structures at flame front compared to stoichiometric and fuel-rich flames. The heat release rate plots indicate that adding hydrogen into ammonia improves the reactivity of the flame and enhances the combustion process. The scatter plots of heat release rate versus local curvature coloured by NO formation, show that high heat release rate values occur in the concave structures and low heat release rate values occur in the convex structure, which is consistent with NO distribution. The highest turbulent burning velocity values were found for the fuel-lean cases due to more wrinkled flame front with lower effective Lewis number compared to fuel-rich cases. The results show a bending effect for the ratio between turbulent to laminar burning velocities with respect to hydrogen addition at all equivalence ratios with 10% hydrogen addition into ammonia exhibiting a highest value for the burning velocity ratio. Two distinct flame structures (concave and convex) were analysed in terms of local equivalence ratio based on the elements of N and O as well as H and O. They revealed an opposite distribution of NO formation normal to the flame front within concave and convex structures. Elementary chemical reactions involved in NO formation have shown that hydrogen addition into ammonia influences the reactivity of certain specific chemical reactions.
Ammonia-hydrogen fuel blends, Direct numerical simulation, Elevated pressure, High turbulence, Premixed combustion
11083 - 11100
Yang, W
48b64780-1118-439a-8b5e-2c686cfc69eb
Ranga Dinesh, K.K.J
6454b22c-f505-40f9-8ad4-a1168e8f87cd
Luo, K.H
fef83745-f037-451c-bf78-f81ba6c88250
Thevenin, D
35a930f2-e8f5-4e0f-b104-6eadb7ee7b73
5 March 2022
Yang, W
48b64780-1118-439a-8b5e-2c686cfc69eb
Ranga Dinesh, K.K.J
6454b22c-f505-40f9-8ad4-a1168e8f87cd
Luo, K.H
fef83745-f037-451c-bf78-f81ba6c88250
Thevenin, D
35a930f2-e8f5-4e0f-b104-6eadb7ee7b73
Yang, W, Ranga Dinesh, K.K.J, Luo, K.H and Thevenin, D
(2022)
Direct numerical simulation of turbulent premixed ammonia and ammonia-hydrogen combustion under engine-relevant conditions.
International Journal of Hydrogen Energy, 47 (20), .
(doi:10.1016/j.ijhydene.2022.01.142).
Abstract
The combustion characteristics of ammonia and ammonia-hydrogen fuel blends under spark-ignited turbulent premixed engine-relevant conditions were investigated by means of direct numerical simulation and detailed chemistry. Several test cases were investigated for an outwardly expanding turbulent premixed flame configuration covering pure ammonia and ammonia-hydrogen fuel blends with 10% and 15% hydrogen content by volume for different equivalence ratio values of 0.9, 1.0 and 1.1. The results showed that the fuel-lean flames exhibit strong wrinkled structures at flame front compared to stoichiometric and fuel-rich flames. The heat release rate plots indicate that adding hydrogen into ammonia improves the reactivity of the flame and enhances the combustion process. The scatter plots of heat release rate versus local curvature coloured by NO formation, show that high heat release rate values occur in the concave structures and low heat release rate values occur in the convex structure, which is consistent with NO distribution. The highest turbulent burning velocity values were found for the fuel-lean cases due to more wrinkled flame front with lower effective Lewis number compared to fuel-rich cases. The results show a bending effect for the ratio between turbulent to laminar burning velocities with respect to hydrogen addition at all equivalence ratios with 10% hydrogen addition into ammonia exhibiting a highest value for the burning velocity ratio. Two distinct flame structures (concave and convex) were analysed in terms of local equivalence ratio based on the elements of N and O as well as H and O. They revealed an opposite distribution of NO formation normal to the flame front within concave and convex structures. Elementary chemical reactions involved in NO formation have shown that hydrogen addition into ammonia influences the reactivity of certain specific chemical reactions.
Text
Yang-et-al-Revised-Manuscript
- Accepted Manuscript
More information
Accepted/In Press date: 18 January 2022
e-pub ahead of print date: 8 February 2022
Published date: 5 March 2022
Additional Information:
Funding Information:
K. H. Luo gratefully acknowledges funding for the research and supercomputing time on ARCHER provided by the UK Engineering and Physical Sciences Research Council (EPSRC) under Grant Nos. EP/S012559/1 and EP/R029598/1 .
Publisher Copyright:
© 2022
Copyright:
Copyright 2022 Elsevier B.V., All rights reserved.
Keywords:
Ammonia-hydrogen fuel blends, Direct numerical simulation, Elevated pressure, High turbulence, Premixed combustion
Identifiers
Local EPrints ID: 455041
URI: http://eprints.soton.ac.uk/id/eprint/455041
ISSN: 0360-3199
PURE UUID: e666588e-91c0-454a-ab4f-8c40d61d07d2
Catalogue record
Date deposited: 04 Mar 2022 17:40
Last modified: 17 Mar 2024 07:08
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Contributors
Author:
W Yang
Author:
K.H Luo
Author:
D Thevenin
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