A Priori Validation of a Multidimensional Turbulent Premixed Combustion Model for High-Pressure Bunsen Flames

ABSTRACT

Recently, the authors proposed a model for the filtered reaction source term conditioned on Favre filtered progress variable in turbulent premixed flames based on filtering of one-dimensional laminar flame profiles. Multidimensional effects from flame propagation at oblique angles through LES filter volumes and from subgrid flame folding were considered by a Gaussian filter kernel and through a wrinkling factor, respectively. Using a DNS database (one-step Arrhenius chemistry, unity Lewis number and constant transport) of statistically flat turbulent flames at different turbulence intensities and at ambient pressure, the model had been validated a priori and some model constants were adapted. Here, the model is validated for a Bunsen flames at varying inlet velocity, turbulence level, turbulent length scale and at higher pressure. In the Bunsen flames at $p=10$ bar, regions of strong curvature reminiscent of Landau-Darrieus instability appear, causing a faster increase of the wrinkling factor at small filter sizes than for the lower pressure flames. The effect is captured by a simple extension of the wrinkling factor model. Very good agreement between model and DNS filtered source term distributions is achieved using this adapted combustion model.

KEYWORDS:

• Turbulent premixed combustion
• high pressure combustion
• LES combustion subgrid model
• wrinkling factor
• Landau-Darrieus-Instability
• turbulent Bunsen flame

Acknowledgements

The first author (MP) would like to thank ITIS e.V. for funding part of this work. The authors thank the Gauss Centre for Supercomputing e.V. (www.gausscentre.eu) for providing computing time on the GCS Supercomputer SuperMUC-NG, at the Leibniz Supercomputing Centre (www.lrz.de).

Disclosure statement

No potential conflict of interest was reported by the author(s).