Numerical study of the effects of laminar flame speed on flame dynamics in the early stages of flame propagation in two-dimensional half open tubes.

The effect of laminar flame speed on the flame dynamics in two-dimensional half open tubes is investigated through a two-dimensional laminar combustion model. Several single-step reaction mechanisms are established to alter the corresponding laminar flame speed. The simulation results show that the similarity of flame propagation only holds during the acceleration phase. In the flame acceleration phase, the flame shape and flame tip position corresponding to each dimensionless moment are almost the same. This similarity gradually disappears after the flame touches the wall. When the flame decelerates, the periodic oscillation of the flame tip velocity is related to the laminar flame speed. The higher the laminar flame speed, the longer the corresponding dimensionless oscillation period. The destruction of this similarity is also reflected in the correlation between the flame surface area and the growth rate of burnt gas volume. In addition, the dimensionless evolution correlation of the flame surface area during the acceleration phase is given in this paper. The moving speed of the flame skirt at different laminar flame speeds and the time interval of flame inversion in the two-dimensional half open tubes are also presented. • Simulation of flame dynamics in a two-dimensional tube under different laminar flame speed. • Simplified mechanisms were established to ensure that only laminar flame speeds were changed in the simulation. • The similarity of flame propagation is destroyed after the flame touches the wall. • The relationship between the volume growth rate of the burned gas and the flame surface was found to be different in the four stages. [ABSTRACT FROM AUTHOR]