Effects of combustor geometry on NH3-CH4 swirling turbulent premixed flames: a combined experimental and large eddy simulation analysis of combustion dynamics and NO emissions

Wang, Ping, Zhang, Jinzhao, Shuai, Ruiyang, Valera-Medina, Agustin ORCID: https://orcid.org/0000-0003-1580-7133, Qian, Weijia, Ferrante, Antonio, Qi, Haotian and Wang, Yongzhi 2025. Effects of combustor geometry on NH3-CH4 swirling turbulent premixed flames: a combined experimental and large eddy simulation analysis of combustion dynamics and NO emissions. International Journal of Hydrogen Energy 180 , 151775. 10.1016/j.ijhydene.2025.151775 Item availability restricted.

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Abstract

Ammonia is a promising zero-carbon fuel for gas turbines but is often blended with methane to enhance combustion. This study investigates the previously unexplored influence of combustor geometry on ammonia-methane premixed swirling flames. Experiments and large eddy simulations (LES) were conducted at an equivalence ratio of 0.85 for a blend of 70 vol% NH3 and 30 vol% CH4, comparing rectangular and cylindrical combustors. The results show distinct flame stabilization mechanisms: wall confinement in the rectangular combustor creates fragmented recirculation zones, whereas the cylindrical geometry promotes a coherent swirling flow. Consequently, the cylindrical combustor generated 1.8 × higher NO emissions (experimentally 2045 ppm vs 1127 ppm), attributed to increased OH radical concentration and higher post-flame temperatures that inhibit NO reduction. These findings suggest rectangular combustors can better balance flame stability with reduced emissions under the studied conditions, providing valuable guidance for designing advanced low-NOx combustors using ammonia fuel blends.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Engineering
Publisher:	Elsevier
ISSN:	0360-3199
Date of First Compliant Deposit:	1 October 2025
Date of Acceptance:	26 September 2025
Last Modified:	02 Oct 2025 09:00
URI:	https://orca.cardiff.ac.uk/id/eprint/181415

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