Computational and experimental study of standing methane edge flames in the two-dimensional axisymmetric counterflow geometry

Journal Article · Sun Oct 15 04:00:00 EDT 2006 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2006.05.006· OSTI ID:20824165

Amantini, Giuliano; Smooke, Mitchell D; Gomez, Alessandro ^[1]; Frank, Jonathan H ^[2]

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1. Department of Mechanical Engineering, Yale Center for Combustion Studies, Yale University, P.O. Box 208286, New Haven, CT 06520-8286 (United States)
2. Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States)

The structure of steady methane/enriched-air edge flames established in an axisymmetric, laminar counterflow configuration was investigated computationally and experimentally. Computationally, the steady-state equations were solved implicitly in a modified vorticity-velocity formulation on a nonstaggered, nonuniform grid, with detailed chemistry and transport. Experimental boundary conditions were chosen to establish flames with a hole centered at the axis of symmetry, the location where the largest strain rate occurs, in order to investigate the structure of the edge flame established at the outer periphery of the hole. Experimentally, CO PLIF, OH PLIF, and an observable proportional to the forward reaction rate (RR) of the reaction CO+OH->CO{sub 2}+H were measured. Particle image velocimetry (PIV) was used to characterize the velocity field in the proximity of the fuel and oxidizer nozzles and to provide detailed boundary conditions for the simulations. Qualitatively, the flow field can be partitioned into two zones: a nonreactive counterflow region bound by two recirculation zones attached at the exits of the inlet nozzles, which aid mixing of products and reactants upstream of the edge flame; and a reactive region, where a premixed edge flame provides the stabilization mechanism for a trailing diffusion flame. Comparisons between the experimental and the computational data yielded quantitative agreement for all measured quantities. Further, we investigated the structure of the computational edge flames. We identified the most significant heat-release reactions for each of the flame branches. Finally, we examined correlations among the propagation speed of the edge flame and curvature and mixture fraction gradient by varying the global strain rate of the flame. (author)

• OSTI ID: 20824165
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 147; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AIR
BOUNDARY CONDITIONS
COMBUSTION KINETICS
COUNTERFLOW SYSTEMS
FLAMES
MATHEMATICAL MODELS
METHANE
STRAIN RATE