Premixed laminar C_3H_8- and C_3H_6-air stagnation flames: experiments and simulations with detailed kinetic models

Abstract

A validation methodology based on the comparison of flame simulations relying on reacting-flow models with experiment is applied to C3 flames. The work reported targets the assessment of the modeled reactions and reaction rates relevant to C3-flame propagation in several detailed combustion kinetic models. A better knowledge of C3 hydrocarbon combustion chemistry is required before attempting to bridge the gap between the reasonably well-understood oxidation of C1–C2 hydrocarbons and the more complex chemistry of heavier hydrocarbons in a single kinetic model. Simultaneous measurements of velocity and CH-radical profiles were performed in atmospheric propane(C3H8)- and propylene(C3H6)-air laminar premixed stagnation flames stabilized in a jet-wall configuration. These nearly flat flames can be modeled by one-dimensional simulations, providing a means to validate kinetic models. Experimental data for these flames are compared to numerical simulations that rely on a 1D hydrodynamic model, a multi-component transport formulation including thermal diffusion, and five different detailed-chemistry models, in order to assess the adequacy of the models employed. The 2005/12 release of the San Diego mechanism is found to have the best overall performance. The logarithmic sensitivities of the simulated flame locations to variations in the kinetic rates are calculated via the "brute-force" method for six representative flames. The kinetic mechanisms used in the analysis are GRI-Mech 3.0 (for reference), the C3 mechanism by Davis-Law-Wang (1999), the latest release (2005/12) of the C1–C3 San Diego mechanism, the 2006/06 release of the C3–C4 unsaturated hydrocarbon mechanism by Battin-Leclerc et al., and Version 0.5 of the C1–C3 mechanism by Konnov (2000).

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