A detailed numerical study of NOx kinetics in counterflow methane diffusion flames: effects of fuel-side versus oxidizer-side dilution

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DOI	Resolve DOI: https://doi.org/10.1155/2021/6642734
Author	Search for: Xu, Huanhuan; Search for: Liu, Fengshan¹; Search for: Wang, Zhiqiang; Search for: Ren, Xiaohan; Search for: Chen, Juan; Search for: Li, Qiang; Search for: Zhu, Zilin
Affiliation	National Research Council Canada. Metrology Research Centre
Format	Text, Article
Abstract	Dilution combustion has been widely utilized due to various merits, such as enhanced efficiency, fewer pollutants emissions, and even a promising future in alleviating global warming. Diluents can be introduced through the oxidizer or fuel side to achieve the desired combustion properties, and H₂O and CO₂ are the most common ones. A comprehensive comparison between the different dilution methods still lacks understanding and optimizes the dilution combustion technologies. This study numerically compared the effects of H₂O and CO₂ dilution in the oxidizer or fuel stream on counterflow methane diffusion flames, emphasizing NO formation kinetics. Results showed that the impact of different radiation heat transfer models on NO emissions diminishes with increasing the dilution ratio. The calculations of radiation heat transfer were treated in three ways: radiation-neglected, optically thin, and using a nongrey radiation model. When keeping the oxygen content and methane fraction constant, CO₂ dilution in the air-side has the most profound influence on NO reduction, and CO₂ dilution in the fuel-side has the least. H₂O dilution showed a medium impact with a larger degree on air-side than that on fuel-side. To gain a deeper understanding of this effect order, the contributions of different NO formation routes were quantified, and analyses were made based on the diluents’ chemical and thermal effects. It was found that the oxidizer-side dilution and fuel-side dilution affect the NO formation pathway similarly. Still, the influence of H₂O dilution on the NO formation pathway differs from that of CO₂ dilution.
Publication date	2021-03-03
Publisher	Hindawi Limited
Licence	Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/
In	Journal of Combustion 2021, 6642734.
Note	yes
Language	English
Peer reviewed	Yes
NRC publication	This is a non-NRC publication "Non-NRC publications" are publications authored by NRC employees prior to their employment by NRC.
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Record identifier	f872d138-7f28-473a-86b4-f4e280e89fd8
Record created	2021-04-12
Record modified	2021-09-21

Date modified:: 2026-02-11