Propagation speed of wrinkled premixed flames within stoichiometric hydrogen-air mixtures under standard temperature and pressure

Abstract

To explore the influence mechanism of initial turbulence on propagation speed of wrinkled flames, the turbulent combustion behavior of wrinkled stoichiometric hydrogen premixed flames was studied in a spherical fanstirred closed vessel under standard temperature and pressure. The variations on flame structure were first observed; turbulent flames first were distorted and then became cellular, and both first and second critical flame radii of cellularity declined with a increased rate as turbulent intensity rose. Then, the variations of stretch effects were compared to laminar flame; the global stretch rate on turbulent flame at a same flame size was raised while the enhancement extent was obviously enlarged with the increase of initial turbulent intensity and/or the growth of flame size. Finally, the variation regulations of propagation speed induced by varying turbulent intensity were analyzed; the nexus between propagation speed and initial turbulence was discussed with the considerations of cellularity phenomenon and stretch effects.