合成气层流预混火焰加速效应实验研究

A systematic investigation on accelerative characteristics of syngas laminar premixed flames is conducted using the visual experimental platform of constant volume combustion chamber. The decoupling control of self‑instability is realized by adjusting the equivalence ratio and oxygen‑nitrogen ratio of gas mixture，allowing for an analysis of flame acceleration stages，onsets，and acceleration exponents. Three distinct stages of laminar flame propagation outwardly are identified，namely quasi‑steady，transitional acceleration，and saturated acceleration. The order of four onsets is as follows：crack branching≈transitional acceleration<uniform cellularity≈ saturated acceleration. The acceleration exponents in saturated acceleration stage are in the range of 1. 1~1. 2，showing independent on Lewis number and density ratio. The results indicate that the flame intrinsic instability can have a significant promotion on the onset of laminar flame acceleration，while it does not affect the flame acceleration strength in saturated acceleration stage.