二次元混合層内に形成された火炎の成長に関する数値シミュレーション : 第2報,燃料の希釈による影響

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This paper deals with numerical simulations of a laminar reactive two-dimensional mixing layer. We have especially focussed on the early stage of flame growth. The effects of fuel dilution and coherent vortices on their flame structures are discussed. The simulations are based on a modified HSMAC method. Fast and slow fluids are the fuel and oxidizer, respectively. The velocity ratio is 4 : 1. The fuel is diluted by nitrogen. An oxygen mass fraction of the oxidizer is fixed at 0.27. The simulations have been applied to three cases of methane mass fractions of 1, 0.3, and 0.2. As a result, it is revealed that three flows occur at the leading edge of the undiluted flame, which are attributed to two separated approach flows and one accelerated flow in the flame. The dilution causes blow-off. Blow-off may well be determined by the first Damkohler number based on the hydrodynamic characteristic time of coherent vortices and the chemical characteristic time of the propagation of the partial premixed flame at the leading edge.
社団法人日本機械学会の論文
1994-07-25