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.
维普
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