The combined effects of chemical reaction order and stoichiometry on nonpremixed edge flames

Abstract

We examined in this work the combined effects of chemical reaction order n and the stoichiometric mixture fraction on the propagation of nonpremixed edge flames in a counterflow configuration. We began by formulating the problem mathematically using the constant density thermo-diffusive model. The problem was then solved numerically using the finite element method. It has been shown that the reaction order and stoichiometry have an interchangeable role in modifying flame propagation. The study has shown that triple flames exist only for a limited range of values of both the chemical reaction order n and the stoichiometric mixture fraction . Over such values, modifying n and were found to have a great impact on many characteristics related to the flame structure, such as the flame location, the extent of both the premixed flame wings and the trilling diffusion flame, and the flame curvature. In addition, the flame location was found to vary subjected to the value of the reaction order in a manner similar to that observed by varying the mixture fraction. The study also identified the influence of the fuel Lewis number on the flame propagation and was found that the effect of is more pronounced when the reaction order differs from unity. Finally, the study has examined the role of the strain rate on the flame propagation and concluded that the effect of the chemical order n is negligible for stoichiometric mixtures but tends to be significant for off-stoichiometric mixtures.