Abstract
Counterflow of methane-air premixed gas and burned gas with active radicals are calculated with detailed kinetics. It was found that the effects of addition of radicals on extinction limits and flame structure are not significant. There are small difference between addition and no addition of radicals. Furthermore, due to the strong radial-direction flow, added radicals are transported to radial direction by convection and diminished. Meanwhile, temperature of countering burned gas has a dominant effect on sustaining premixed flames. High-temperature burned gas affects weak flame and its extinction limits are extended. These results agree well with the results of counterflow flames of propane-air premixed gas and burned gas conducted by Darabiha et al. [Darabiha, N., et al., Combust. Sci. Tech., 60 (1988), 267.].
