Abstract: Structure and dynamics of near-limit premixed flames in narrow channels are numerically studied. The channel consists of two circular parallel plates, one of which is upward and another is downward. It is possible that the premixed flame is stable when the mixture of fuel gas and oxygen in the channel is ignited. A reaction-diffusion model is used based on the Arrhenius-type chemistry, and attention is focused on the influence of distance between two plates as well as the plate’s material and radius. There are mainly two steady solutions for a given distance between the plates, a small flame and a large flame. Linear stability analysis shows that 1D stable flames may exist in the narrow channel, but 2D stable flames do not exist. The dynamical evolution processes of 1D stable, but 2D unstable flames are studied by direct numerical simulations. It is shown that the flame drifts to the boundary as a whole or an old one splits into two new flames that drift to the boundary along the opposite direction.

Key words: flammability limit, narrow channel, premixed flame, stability