メタン-空気ブンゼン火炎の数値解析 : 第2報, 火炎基部および内炎先端, 外炎先端の構造

概要

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A methane-air premixed flame with and equivalence ratio of 1.25 was simulated with a model including 91 pairs of elementary reactions occurring among 29 species. In this second part, the flame structures at the base of the flame and at inner and outer cone tips are discussed. Around the burner rim, the entrainment of air from the surroundings is seen to be the main reason for the activation of chemical reactions by promoting large production of O atoms and OH radicals. As a consequence, the rate of heat release there is very large, allowing the flame temperature to increase steeply and the flame to be held on the burner. At the inner cone tip, also, chemical reactions proceed with large rates, due to flame stretch and to preferential diffusion of H_2. H_2 is consumed there, so that the fuel burning at the inner cone tip is composed of a mixture of CH_4+H_2. CH_3 radicals remain above the inner cone tip and, around the tip of the outer cone, oxidation via C_1 route leads to formation of CO, which is oxidized into CO_2, as in any other point of the outer cone. H_2, however, is formed by reduction of water above the inner cone tip. This H_2 formation continues even within and above the outer cone tip, so that respect to H_2 the outer cone is found to have no tip.
社団法人日本機械学会の論文
1996-01-25