Flamelet-based modeling of NO formation in turbulent hydrogen jet diffusion flames
- Centre National de la Recherche Scientifique, Orleans (France). Lab. de Combustion et Systemes Reactifs
- Univ. of California, Berkeley, CA (United States). Dept. of Mechanical Engineering
The potential of using the laminar flamelet model for predictions of NO{sub x} emissions from turbulent hydrogen jet diffusion flames with various amounts of helium dilution is explored in this study. The flamelet approach treats turbulent flames as an ensemble of laminar flames subject to local fluid dynamic stretch which causes chemical kinetics to deviate from equilibrium. This flame stretch rate can be described as the scalar dissipation rate or as the strain rate. Numerical modeling is performed to assess the merits of these two choices by comparing predicted scaling behavior of NO{sub x} emission index with the experimental data of Driscoll and co-workers. The present study reveals that only with the scalar dissipation rate as the nonequilibrium parameter will the predicted NO{sub x} emission indices exhibit a clear scaling relation vs the Damkoehler number. The flamelet predictions are found to improve when the Damkoehler number increases. However, the absolute NO{sub x} levels are overpredicted, which is attributed to differential diffusion effects.
- OSTI ID:
- 543498
- Journal Information:
- Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 111; ISSN CBFMAO; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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