The structure and extinction of partially premixed flames burning methane in air

Results of experimental and numerical studies of counterflow, partially premixed, flames burning methane in air are reported. Experimental data is obtained for the temperature profile, the axial velocity profile, the concentration profiles of various stable species and the critical conditions of the flame at extinction. The results are compared with numerical calculations performed at conditions identical to those used in the experiment. Experimental measurements and numerical calculations show that partial premixing of the reactant streams of a counterflow diffusion flame makes the flame less resistant to stretch. In addition, numerical calculations show that the reaction zone of a partially premixed flame exhibits a diffusion flame and a premixed flame-like structure. Both results are consistent with previous asymptotic analyses of the structure of partially premixed flames.