C124 水素・空気予混合火炎の局所構造に対する乱流特性長さの影響

概要

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Direct numerical simulations of H_2-air turbulent premixed flames propagating in two-dimensional homogeneous isotropic turbulence are conducted to investigate the effects of turbulence characteristic length scale on the local flame structure. The integral length scales are selected to be 2.42,4.84 and 7.26 times of laminar flame thickness, while the ratio of turbulence intensity to the laminar flame speed is kept to be constant : u'_<rms>=20.0S_L. Detailed kinetic mechanism with 12 reactive species and 27 elementary reactions is used to represent the H_2-O_2-N_2 reaction in turbulence. Turbulent burning velocity decreases with the decrease of integral length scale. The reaction zone becomes much narrower and the flame front becomes shorter with the decrease of integral length scale, whereas, the overall flame patterns are similar. For the case of l/δ_L=2.42,the variation of the local heat release rate along the flame fronts is much higher and the maximum heat release rate reaches to 2.4 times of laminar flame.
日本流体力学会の論文
2000-07-25