Interactions of diffusion flames in an opposed-jets flow

By using an opposed-jets flow composed of an upper single jet and a lower coaxial jet, a planar diffusion flame located near the stagnation plane and a trumpet-shaped diffusion flame stabilized along the interface of coflowing jets were experimentally developed to simulate and study diffusion burning structures modified by interactions of oxidizer eddies within fuel zone in turbulent combustible flows. It was shown that in comparison with the trumpet-shaped flame, the planar flame is not only easier to be stabilized in the given flow field, but also easier to generate soot layer; and that the propane flame has better flame stabilization and is relatively sooty than the methane flame. Interaction and transition of two diffusion flames further indicated that the development of a diffusion flame is strongly influenced by its own oxygen supply, and may be sensitive to oxygen supply of the other stronger flame; and that soot formation strongly depends on oxygen and fuel supplies, and fuel region being closed by the flame or not. In this study, detailed comparisons on individual diffusion flames and discussions on interaction and transition of two diffusion flames therefore enrich our understandings on interactions of diffusion flamelets in the turbulent flow.