Journal Article

FZJ-2026-00855

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Laminar and turbulent hydrogen-enriched methane flames: Interaction of thermodiffusive instabilities and local fuel demixing

Nicolai, H. (Corresponding author) ; Schuh, V. ; Bähr, A. ; Schneider, M. ; Rong, F. ; Kaddar, D. ; Bode, M.FZJ* ; Hasse, C.

2025
Elsevier Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.proci.2025.105885  doi:10.34734/FZJ-2026-00855

Abstract: Blending hydrogen with methane provides a practical approach for transitioning existing energy infrastructure to hydrogen-based carriers. However, under fuel-lean conditions, increasing the hydrogen content causes flames to transition rapidly from methane-like combustion to hydrogen-dominated flames, primarily driven by thermodiffusive instabilities that significantly enhance turbulent flame speeds. This study systematically examines lean methane/hydrogen/air flames of varying complexity, from three-dimensional laminar unstable cases to turbulent jet flames at two different Reynolds numbers, with an emphasis on the impact of the distinct molecular transport properties of hydrogen and methane. The large-scale simulations reveal that these blends exhibit instabilities even under turbulent conditions, albeit to a lesser degree than pure hydrogen flames. Nonetheless, synergistic interactions between turbulence and thermodiffusive instabilities lead to notable increases in turbulent flame speed and reactivity factors ($I_0$) at higher Reynolds/Karlovitz numbers. Moreover, beyond the effects of overall non-unity Lewis number, the different diffusivity of hydrogen and methane (i.e., non-equal Lewis numbers) significantly influence the formation and intensity of intrinsic flame instabilities. These findings underscore the importance of thermodiffusive instabilities in methane/hydrogen combustion and highlight the need for advanced modeling approaches capable of capturing local demixing effects under turbulent flows conditions.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 5112 - Cross-Domain Algorithms, Tools, Methods Labs (ATMLs) and Research Groups (POF4-511) (POF4-511)
2. Inno4Scale - Innovative Algorithms for Applications on European Exascale Supercomputers (101118139) (101118139)

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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