摘要
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 constant-volume combustion vessel and high-speed schlieren camera system were employed to obtain the outwardly propagating spherical flames of ethanol-hydrogen-air mixtures.The effect of hydrogen fraction on the flame instability was analyzed by using the flame schlieren images and flame instability theory.The results show that,for the lean mixture combustion the cracks of flame front increase with hydrogen addition,indicating that the flame instability increases with the increase of the hydrogen fraction,while the opposite effect is observed at the rich mixture combustion.With the addition of the hydrogen,the variation trend of diffusional-thermal consists with that of global instability.With the increase in hydrogen fraction,the change trend of flame hydrodynamics instability is determined by the changes of the flame thickness and thermal expansion ratio.The change of hydrodynamics instability cannot change the variation trends of diffusional-thermal and global instability.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2014年第4期787-791,共5页
Journal of Engineering Thermophysics
基金
湖北省自然科学基金重点项目(No.2011CDA058)
交通运输部应用基础研究项目(No.2013319811140)
关键词
乙醇
氢气
定容燃烧弹
球形火焰
不稳定性
ethanol
hydrogen
constant-volume combustion vessel
spherical flame
instability
