Flame acceleration in a channel: effects of the channel width and wall roughness

Results of numerical simulations of flame acceleration in a semi-open channel filled by acetylene-based mixtures are reported. The computations are performed by the advanced dissipationless method CABARET. The effects of the channel width and the roughness of the inner wall of the channel on the flame evolution dynamics at various stages of the flame acceleration process are demonstrated based on comparisons of results obtained in different formulations. In particular, it is shown that the flame velocity and the amplitude of velocity fluctuations at the quasi-steady stage of flame propagation increase with an increase in the channel width. It is also demonstrated that flow deceleration at the channel walls produces the most pronounced effect at the stage of quasi-steady propagation of the flame owing to faster development of the boundary layer and vortex generation in the near-wall region and vortex interaction with the flame extended along the channel walls.