火炎の伸張率を制御したメタン/空気拡散エッジ火災の構造と伝播(熱工学,内燃機関,動力など)

概要

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The structure and propagation properties of edge flames were investigated for counter flow strain-controlled CH4/air diffusion flames. Numerical computations incorporating detailed chemical kinetics and multicomponent diffusion were performed focusing on effects of strain (stretch) rate on edge flame structure and burning velocity. These computations gave the following results. (1) When the stretch rate is low, the edge flame forms a hook-like shape where the structure corresponds to a premixed flame in the radial direction and a diffusion flame in the axial direction. The local burning velocity varies from point to point in the equivalence ratio. The maximum local burning velocity observed at the tip of the flame front is lower than that of the maximum burning velocity of one-dimensional premixed flame of the same fuel. (2) The local burning velocity is influenced not only by the local eqivalence ratio but also by the main flame propeties of the high-temperature burnt gas, where the different equivalence ratio prevails. (3) For a high stretch rate, the burning velocity is negative. The negative burning valocity means that the receding velocity of edge flame is higher than the radial fluid velocity component because of flame-edge quenching. The flame edge of the negative burning velocity is a sharp edge with equicontours of the heat-elease rate.
一般社団法人日本機械学会の論文
2004-02-25