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A comparative analysis of plasma and hydrogen effects on premixed ammonia combustion

Shahsavari, Mohammad ; Chakraborty, Nilanjan ; Konnov, Alexander A. LU ; Zhong, Shenghui ; Valera-Medina, Agustin and Jangi, Mehdi (2025) In Combustion and Flame 279.
Abstract

In this study, we use direct numerical simulations to investigate turbulent premixed ammonia flames assisted by non-equilibrium nanosecond plasma discharges and hydrogen addition. The results reveal the coupling effects of turbulence, the hydrogen concentration in the fuel blend, and plasma discharges on the microscopic structure of the flame and chemical pathways. It is found that the flame front assisted by plasma is more distributed, whilst 58 % less stretched when compared to the hydrogen-enriched un-assisted flame. Additionally, turbulence has more pronounced effects on the hydrogen-enriched flame, broadening the flame brush. A comparison of the reaction pathways contributing to the heat release indicates that turbulence shifts the... (More)

In this study, we use direct numerical simulations to investigate turbulent premixed ammonia flames assisted by non-equilibrium nanosecond plasma discharges and hydrogen addition. The results reveal the coupling effects of turbulence, the hydrogen concentration in the fuel blend, and plasma discharges on the microscopic structure of the flame and chemical pathways. It is found that the flame front assisted by plasma is more distributed, whilst 58 % less stretched when compared to the hydrogen-enriched un-assisted flame. Additionally, turbulence has more pronounced effects on the hydrogen-enriched flame, broadening the flame brush. A comparison of the reaction pathways contributing to the heat release indicates that turbulence shifts the key reactions producing heat from HNO+H⬄NO+H2 and OH+H2⬄H + H2O to NH2 dissociation reactions. Additionally, NOx emissions are more influenced by thermal effects in the hydrogen-enriched flame, with NO concentration being 35 % higher than in the plasma-assisted flame. The higher NOx emissions in the hydrogen-enriched flame are attributed to the higher concentration of H radicals, which react with HNO and produce NO.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Direct numerical simulation, Nanosecond-pulsed plasma discharge, NH/H flames
in
Combustion and Flame
volume
279
article number
114300
publisher
Elsevier
external identifiers
  • scopus:105008512893
ISSN
0010-2180
DOI
10.1016/j.combustflame.2025.114300
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 The Authors
id
3400f7ec-5355-4146-a05e-7d9bc4015c4b
date added to LUP
2025-11-24 15:57:17
date last changed
2025-11-24 15:57:52
@article{3400f7ec-5355-4146-a05e-7d9bc4015c4b,
  abstract     = {{<p>In this study, we use direct numerical simulations to investigate turbulent premixed ammonia flames assisted by non-equilibrium nanosecond plasma discharges and hydrogen addition. The results reveal the coupling effects of turbulence, the hydrogen concentration in the fuel blend, and plasma discharges on the microscopic structure of the flame and chemical pathways. It is found that the flame front assisted by plasma is more distributed, whilst 58 % less stretched when compared to the hydrogen-enriched un-assisted flame. Additionally, turbulence has more pronounced effects on the hydrogen-enriched flame, broadening the flame brush. A comparison of the reaction pathways contributing to the heat release indicates that turbulence shifts the key reactions producing heat from HNO+H⬄NO+H<sub>2</sub> and OH+H<sub>2</sub>⬄H + H<sub>2</sub>O to NH<sub>2</sub> dissociation reactions. Additionally, NOx emissions are more influenced by thermal effects in the hydrogen-enriched flame, with NO concentration being 35 % higher than in the plasma-assisted flame. The higher NOx emissions in the hydrogen-enriched flame are attributed to the higher concentration of H radicals, which react with HNO and produce NO.</p>}},
  author       = {{Shahsavari, Mohammad and Chakraborty, Nilanjan and Konnov, Alexander A. and Zhong, Shenghui and Valera-Medina, Agustin and Jangi, Mehdi}},
  issn         = {{0010-2180}},
  keywords     = {{Direct numerical simulation; Nanosecond-pulsed plasma discharge; NH/H flames}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Combustion and Flame}},
  title        = {{A comparative analysis of plasma and hydrogen effects on premixed ammonia combustion}},
  url          = {{http://dx.doi.org/10.1016/j.combustflame.2025.114300}},
  doi          = {{10.1016/j.combustflame.2025.114300}},
  volume       = {{279}},
  year         = {{2025}},
}