Numerical analysis of a methane-air bunsen flame (2nd report, structures near the burner rim and at inner and outer cone tips)

A methane-air premixed flame with equivalence ratio of 1.25 is simulated focusing on the flame structures at the base of the flame and at inner and outer cone tips. Around the burner rim, the entrainment of air from the surrounding is seen to be the main reason for the activation of chemical reactions by promoting large production of O atoms and OH radicals. At the inner cone tip, chemical reactions proceed with large rates, due to flame stretch and to preferential diffusion of H₂. CH₃ radicals remain above the inner cone tip and around the tip of the outer cone, and oxidation via C₁ route leads to formation of CO which is oxidized into CO₂, as in any point of the outer cone.