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利用定容燃烧弹高速纹影摄像系统所得到的向外传播球形火焰纹影图片,并结合火焰不稳定性理论分析了掺氢对乙醇-空气预混火焰不稳定性的影响规律.结果表明,随着掺氢量的增加,在稀薄混合时火焰不稳定性增加,表现为前锋面的裂纹加剧;而在浓混合时呈现相反的变化趋势.可燃混合物的热扩散不稳定性与综合不稳定性随掺氢量的变化趋势一致;流体力学不稳定性不影响热扩散不稳定性与综合不稳定性的变化趋势,它随掺氢量的变化取决于火焰厚度和热膨胀比的综合变化。
The influence of hydrogen addition on the instability of ethanol-air premixed flame was analyzed by using the out-spread spherical flame grain image obtained from the high-speed grazing camera system of constant volume combustion bomb. With the increase of hydrogen addition, the flame instability increases with the lean mixing, which shows that the crack of the front face aggravates, while the trend of the change is opposite in the rich mix.The thermal diffusivity instability and the comprehensive instability of the flammable mixture The results show that the hydrodynamics instability does not affect the trend of thermal diffusivity instability and general instability. The change of hydrogen doping quantity depends on the comprehensive changes of flame thickness and thermal expansion ratio.