자유롭게 전파하는 $CH_4$/$O_2$/$N_2$ 예혼합화염에서 산소부화에 따른 화염구조

The Flame Structure of Freely Propagating $CH_4$/$O_2$/$N_2$ Premixed Flames on Adding Oxygen

Numerical simulations of freely propagating flames burning stoichiometric $CH_4$/$O_2$/$N_2$ mixtures are performed at atmospheric pressure in order to understand the effect of the $O_2$ enrichment level on $CH_4$/Air flame. A chemical kinetic mechanism is employed, the adopted scheme involving 54 gas-phase species and 632 forward reactions. The calculated flame. speeds are compared with the experiments for the flames established at several $O_2$ enrichment level, the results of which is in excellent agreement. As a result of the increased $O_2$ enrichment level from 0.21 to 1, the mole fraction of CO in the burned gas is increased. The flame speed and the temperature in the burned gas are also increased, but the thickness of the flame is severely shrunken in the preheat region.