Numerical simulation of the influence of partial premixing on the propagation of partially premixed flames

This paper examines the influence of a partial premixing between the reactants prior to the reaction in a mixing layer on the structure and propagation of triple flames formed in this configuration. The problem has been mathematically formulated in the framework of the thermo-diffusive model under a single-step irreversible chemical reaction. A computational modeling and numerical simulations based on finite elements were then employed to solve the governing equations. The study has shown that the flame structure and characteristics such as its speed and maximum temperature were significantly modified in the presence of premixing. The triple flame structure were found to exhibit several changes such as the shift of the leading edge toward the combustion mixture side, the weakening of the upper premixed branch, and the increase in the flame area. It has been predicted that the premixing can substantially enhance the reactivity of the combustion mixture, but on the other hand it tends to shift the flame to the boundary which may destroy the combustion chamber.