The impact of soret diffusion on the product gas characteristics of premixed laminar ammonia/hydrogen/air flames stabilised in a stagnation flow

Kovaleva, Marina ORCID: https://orcid.org/0000-0002-6516-3658, Gotama, Gabriel, Hayakawa, Akihiro, Okafor, Ekenechukwu C., Colson, Sophie, Crayford, Andrew ORCID: https://orcid.org/0000-0002-6921-4141, Kudo, Taku and Kobayashi, Hideaki 2023. The impact of soret diffusion on the product gas characteristics of premixed laminar ammonia/hydrogen/air flames stabilised in a stagnation flow. Presented at: 14th Asia-Pacific Conference on Combustion, Kaohsuing, Taiwan, 14 -18 May 2023. Proceedings of the 14th Asia-Pacific Conference on Combustion.

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Abstract

Accurate prediction of ammonia/hydrogen flame emissions is important towards an efficient low-carbon energy future and requires accurate modelling of molecular diffusion to account for hydrogen’s high diffusivity. The present work investigates the contribution of the Soret effect to molecular diffusion in a laminar burner-stabilised stagnation flame configuration using a blend of ammonia/hydrogen/air. Addition of the Soret effect in the diffusion model changes the predicted emissions of NO, increases the prediction of NO2, and reduces N2O and H2 predictions. Diffusion flux analysis shows that the Soret effect acting directly on the molecule is predominantly responsible for changes in NO2 and H2 profiles. However, NO and N2O emissions were indirectly affected by Soret diffusion through a change in rates of reaction involving these molecules. In the lean condition, the Soret effect drives enrichment in the flame zone through promoting H2 diffusion towards the flame front and shifting the flame upstream. In the rich condition, enrichment of the post-flame zone through enhanced NH3 and H2 diffusion increases reaction rates of NO and shifts the flame downstream. Therefore, this study informs the underlying behaviours of the Soret effect in influencing ammonia/hydrogen flame chemistry.

Item Type:	Conference or Workshop Item (Paper)
Status:	In Press
Schools:	Engineering
Subjects:	T Technology > TJ Mechanical engineering and machinery
Date of First Compliant Deposit:	18 May 2023
Date of Acceptance:	15 May 2023
Last Modified:	14 Jul 2023 01:30
URI:	https://orca.cardiff.ac.uk/id/eprint/159590

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