Investigations on the Flamelet Inner Structure of Turbulent Premixed Flames

International audiencePlanar Rayleigh scattering measurements were used to investigate the inner structure of flamelets in premixed turbulent Bunsen flames. Measurements were performed in a high pressure chamber, where pressure is varied from 0.3 to 0.9 MPa. Two lean equivalence ratios (0.6 and 0.7) of methane=air mixtures were studied. Local information regarding the thickness and the local curvature of the flamelets were obtained. It is observed that an increase of the equivalence ratio induces a decrease of the mean local flamelet thickness. When pressure is increased from 0.3 to 0.9 MPa, the mean flamelet thickness does not decrease as for laminar case. The different external phenomena (turbulence and stretch (curvature and strain rate)) which could explain this trend are investigated