Numerical studies of vortex-induced extinction/reignition relevantto the near-field of high-Reynolds number jets

• Published in: Physics of fluids (1994) 2009-05, Vol.21 (5), p.055106-055106-11
• Main Authors: Venugopal, Rishikesh, Abraham, John
• Format: Article
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/1.3139308

This work is motivated by the need to understand physical mechanisms governing near-field phenomena, such as flame lift-off, in high-Reynolds number jet flames. Numerical studies of vortex-induced flame extinction/reignition are performed for conditions representative of the near field of high-Reynolds number ( ∼ 100 000 ) jets under high pressure and temperature conditions. The governing equations for compressible, viscous, and reacting flows are solved along with a single-step irreversible chemical kinetic model for gaseous n -heptane oxidation. Extinction/reignition phenomena, influenced by unsteady and curvature effects, are observed. Unsteady flamelet/progress variable models are shown to accurately describe the flame response during extinction/reignition observed in the flame-vortex studies. Furthermore, while unsteady effects on extinction/reignition are found to diminish with weaker vortices and relatively strong flames, curvature effects are found to increase with relatively thicker flames. The observed flame-vortex interaction regimes are summarized on an outcome diagram, which is useful to understand the nature of localized flame dynamics in the near field of jet flames.