1. Influence of buoyancy on the mixing, flame structure, and production of NO in hydrogen diffusion flames.
- Author
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Manatunga, Manahara, Christo, Farid C., Schluter, Jorg, and Shelyag, Sergiy
- Subjects
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HYDROGEN flames , *BUOYANCY , *COMPUTATIONAL fluid dynamics , *FLAME , *HYDROGEN production , *REYNOLDS number - Abstract
This study investigates the impact of buoyancy on the mixing and flame structure of hydrogen jet diffusion flames. A validated Computational Fluid Dynamics (CFD) model for hydrogen diffusion flames is developed, employing the k − ω turbulence model and a steady flamelet combustion model. By accounting for the buoyancy term, the model accurately predicts the stoichiometric hydrogen flame length within a mere 0.2% deviation from the experimental value. In contrast, excluding the buoyancy term leads to a prediction divergence of around 5%. Deeper analysis of the mixture fraction field indicates that buoyancy enhances mixing in the flame's far-field region, facilitating a more rapid dilution of the fuel stream within the air. This, in turn, results in a shorter flame. The scope of the modelling is expanded to encompass buoyancy effects on hydrogen flames with jet Reynolds numbers (R e J ) up to 15,000. While the buoyancy's influence on flame control weakens as R e J increases, a noticeable ∼ 4% variation in stoichiometric flame length persists between scenarios with and without buoyancy. • Accounting for buoyancy enhances H 2 flame prediction accuracy in CFD simulations. • Buoyancy boosts fuel-air mixing; its impact on reaction kinetics is negligible. • Buoyancy effect weakens with increasing jet velocity, but remains noticeable. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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