Abstract
Flame structures of Turbulent N_2 diluted CH_4 flames impinging with a lean CH_4 premixed flame near the extinction conditions are studied experimentally. Triple boundaries, lean premixed flame surface, lean diffusion flame surface and impinging surface are visualized simultaneously by a laser tomography technique using different tracer particles. The turbulent N_2 diluted CH_4 gas can be reacts with the high temperature burnt gas from the lean premixed flame. Approaching the extinction conditions, the local quenching occurs. The local quenching becomes main trigger to develop the global extinction. However, more than half of local quenching can be recovered by themselves.
