A novel flamelet manifold parametrization approach for lean CH4–H2-air flames

Luo, Yujuan; Ferraro, Federica; Breicher, Adrian; Böttler, Hannes; Dreizler, Andreas; Geyer, D.; Hasse, Christian; Scholtissek, Arne

doi:10.1016/j.ijhydene.2022.09.233

Cited by 5 publications

(1 citation statement)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several previous analyses 14 – 18 considered different choices of reaction progress variables based on normalized mass fractions of , major species, fuel and product mass fractions and non-dimensional temperature for hydrocarbon fuels where the effects of preferential diffusion of heat and species are not strong. While several studies have already dealt with this aspect for compound fuel mixtures consisting of hydrogen and hydrocarbons 19 – 26 , it has rarely been addressed in the existing literature for syngas where the effect of preferential diffusion plays a key role, and the current analysis fills this gap. The present work analyses the effects of preferential diffusion on the normalized species profiles within the flame front in syngas-air premixed flames under different mixture compositions and turbulence intensities.…”

Section: Introductionmentioning

confidence: 98%

Choice of reaction progress variable under preferential diffusion effects in turbulent syngas combustion based on detailed chemistry direct numerical simulations

Wehrmann,

Chakraborty,

Klein

et al. 2024

Sci Rep

View full text Add to dashboard Cite

The combustion of hydrogen and carbon-monoxide mixtures, so-called syngas, plays an increasingly important role in the safety context of non-fossil energy generation, more specifically in the risk management of incidents in process engineering plants for ammonia synthesis and in nuclear power plants. In order to characterize and simulate syngas/air combustion on industrially relevant scales, subgrid modelling is required, which is often based on a reaction progress variable. To understand the influence of different fuel compositions, turbulence intensities and flame topologies on different possible definitions of reaction progress variable, detailed chemistry direct numerical simulations data of premixed, lean hydrogen/air and syngas/air flames has been considered. A reaction progress variable based on normalized molecular oxygen mass fraction has been found not to capture the augmentation of the normalized burning rate per unit flame surface area in comparison to the corresponding 1D unstretched premixed flame due to preferential diffusion effects. By contrast, reaction progress variables based on other individual species, such as hydrogen, can capture the augmentation of the rate of burning well, but exhibit a pronounced sensitivity to preferential diffusion effects, especially in response to flame curvatures. However, a reaction progress variable based on the linear combination of the main products can accurately represent the temperature evolution of the flame for different mixtures, turbulence intensities and varying local flame topology, while effectively capturing the augmentation of burning rate due to preferential diffusion effects. However, its tendency to assume values larger than 1.0 in the regions of super-adiabatic temperatures poses challenges for future modeling approaches, whereas the reaction progress variable based on hydrogen mass fraction remains bound between 0.0 and 1.0 despite showing deviations in comparison to corresponding variations obtained from the unstretched laminar flame depending on flame curvature variations.

show abstract