メタン-空気ブンゼン火炎の数値解析 : 第1報,内炎および外炎の構造

概要

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A methane-air premixed flame with an equivalence ratio of 1.25 was simulated with a model including 91 pairs of elementary reactions occurring among 29 species. In this first work, the structure of a representative transversal section of the flame is presented and the mechanisms of combustion at the inner and outer cones are discussed in detail. CH_4 and O_2 in the mixture both react with H atoms, but the reaction between CH_4 and H occurs preferentially to that between O_2 and H at the fuel side of the inner cone. This results in a lack of oxygen atoms at the position where CH_4 breaks into CH_3 radicals and the reactions belonging to the C_2 route proceed with higher velocities than those belonging to the C_1 route. The consumption of O_2, being posterior to the consumption of CH_4, produces O atoms at the center of the inner cone. These O atoms, though not abundant, are sufficient to oxidize the last stable product of the C_2 route, C_2H_2, preventing soot production. The diffusion of H atoms from the flame front to low-temperature regions and the subsequent production of OH radicals were found to be essential to the stability of both inner and outer cones, by triggering the combustion chain reactions.
社団法人日本機械学会の論文
1995-12-25