A Study of the Laminar Flame Tip and Implications for Premixed Turbulent Combustion

TLDR: In this paper, the authors investigated the displacement speed of a curved flame in a non-uniform flow field, and showed that three different mechanisms affect the displacement of a curve flame in such a flow field: a chemical mechanism associated with the expansion of the reaction zone structure, a hydrodynamic mechanism due to isothermal area modification by lateral flow divergence, and a linear flow divergence.

Abstract: Flame surface curvature is a significant geometrical parameter that affects the structure and propagation of premixed laminar and turbulent flames. In this study, the flame tip of a two-dimensional laminar Bunsen burner is investigated using a quasi-one dimensional model, direct numerical simulations and experimental results. The laminar flame tip is a simple prototype of curved flamelets embedded in a turbulent flow field. It is shown that two characteristic flame speeds are necessary to give a local description of a given flamelet: the consumption speed associated with the structure of the reaction zone, and the displacement speed of the flame front relative to the unburned flow. The quasi-one dimensional model shows that three different mechanisms affect the displacement speed of a curved flame in a non-uniform flow field: a chemical mechanism associated with the expansion of the reaction zone structure, a hydrodynamic mechanism due to isothermal area modification by lateral flow divergence an...