Regimes of non-premixed flame-vortex interactions

Thévenin, Dominique; Renard, Paul-Henri; Fiechtner, Gregory J.; Gord, James R.; Rolon, Juan-Carlos

doi:10.1016/s0082-0784(00)80619-0

Cited by 32 publications

(28 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 11 shows the outcome diagram constructed in terms of l r and u fv as axes, consistent with prior numerical 45 and experimental 44 works. In Fig.…”

Section: -3supporting

confidence: 74%

“…Hence, the present results indicate that at downstream jet locations and/or radial locations far from the jet centerline, we are likely to encounter regimes characterized by pocket formation without extinction due to the presence of relatively smaller ͑l r Ͻ 0.3͒ and relatively slower ͑u fv Ͻ 2͒ vortices. Experiments of Thevenin et al 44 in vortex-perturbed hydrogen flames have shown evidence of such regimes for relatively small vortex-to-flame length scale ratios ͑0.1Ͻ l r Ͻ 1.0͒. Furthermore, as discussed by Thevenin et al, 44 below a certain vortex size ͑l r Ͻ 0.1͒, the effect of the vortex on the flame structure would be mitigated by viscous effects.…”

Section: -3mentioning

confidence: 89%

“…Experiments of Thevenin et al 44 in vortex-perturbed hydrogen flames have shown evidence of such regimes for relatively small vortex-to-flame length scale ratios ͑0.1Ͻ l r Ͻ 1.0͒. Furthermore, as discussed by Thevenin et al, 44 below a certain vortex size ͑l r Ͻ 0.1͒, the effect of the vortex on the flame structure would be mitigated by viscous effects.…”

Section: -3mentioning

confidence: 89%

See 2 more Smart Citations

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

Venugopal

Abraham

2009

Physics of Fluids

View full text Add to dashboard Cite

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 ͑ϳ100 000͒ 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.

show abstract

“…Figure 11 shows the outcome diagram constructed in terms of l r and u fv as axes, consistent with prior numerical 45 and experimental 44 works. In Fig.…”

Section: -3supporting

confidence: 74%

Section: -3mentioning

confidence: 89%

Section: -3mentioning

confidence: 89%

See 1 more Smart Citation

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

Venugopal

Abraham

2009

Physics of Fluids

View full text Add to dashboard Cite

show abstract

“…It is important to note that the order of magnitude estimates presented in this section, leading to conditions (25), (27), and (28), could be used to extend existing diagrams of diffusion-flame/vortex interaction regimes [21] in the limit of strong vortices considered here.…”

Section: Order-of-magnitude Estimatesmentioning

confidence: 88%

“…This kind of interaction provides relevant information such as the time evolution of the flame front and the flame structure, as well as information on extinction limits, pocket formation, effects of vortex size and strength, etc. Numerical and experimental studies of local flame extinction in flame/vortex interactions [18][19][20] also lead to improved definitions of the different regimes in turbulent combustion diagrams, which summarize the current knowledge in the field [21,22].…”

Section: Introductionmentioning

confidence: 99%

On the dynamics of flame edges in diffusion-flame/vortex interactions

Hermanns

Vera

Liñán

2007

Combustion and Flame

View full text Add to dashboard Cite

We analyze the local flame extinction and reignition of a counterflow diffusion flame perturbed by a laminar vortex ring. Local flame extinction leads to the appearance of flame edges separating the burning and extinguished regions of the distorted mixing layer. The dynamics of these edges is modeled based on previous numerical results, with heat release effects fully taken into account, which provide the propagation velocity of triple and edge flames in terms of the upstream unperturbed value of the scalar dissipation. The temporal evolution of the mixing layer is determined using the classical mixture fraction approach, with both unsteady and curvature effects taken into account. Although variable density effects play an important role in exothermic reacting mixing layers, in this paper the description of the mixing layer is carried out using the constant density approximation, leading to a simplified analytical description of the flow field. The mathematical model reveals the relevant nondimensional parameters governing diffusion-flame/vortex interactions and provides the parameter range for the more relevant regime of local flame extinction followed by reignition via flame edges. Despite the simplicity of the model, the results show very good agreement with previously published experimental results.

show abstract