异丁醇/辛酸甲酯混合燃料预混层流火焰速度的研究

针对生物柴油与醇类混合燃料燃烧机理研究的需求,采用高速纹影光学诊断方法和定容燃烧弹系统试验研究了异丁醇/辛酸甲酯混合燃料的预混层流燃烧特性。测量了不同当量比和初始压力条件下的不同配比混合燃料—空气预混合气的层流燃烧火焰速度,火焰拉伸率以及马克斯坦长度。分析了燃烧初始条件及异丁醇掺混比例对混合燃料的无拉伸层流燃烧速度及火焰不稳定性的影响规律。结果表明:异丁醇/辛酸甲酯混合燃料的拉伸层流火焰传播速度和层流火焰燃烧速度随着当量比的增加先增加后减少,随着初始压力的增加而减小;马克斯坦长度随着当量比和初始压力的增加而减小;异丁醇掺混比例的增加加快了层流火焰燃烧速度,但使得火焰的不稳定性倾向增加。

Study Of Premixed Laminar Flame Speed of Iso-butanol / Methyl Octanoate Blended Fuel

In order to research the combustion mechanism of biodiesel/alcohol blended fuel, the premixed laminar combustion characteristics of iso-butanol/methyl octanoate were studied by using high-speed schlieren photography and constant-volume combustion vessel. The laminar burning veloci-ty, flame stretch rate and Markstein length of the premixed fuel/air mixture at different equivalence ratio, initial pressure and iso-butanol blending ratio were measured. The effects of the initial combustion conditions and the ratio of iso-butanol on the unstretched laminar burning velocity and flame instability were analyzed. The results show that both the stretched laminar propagation velocity and laminar burning velocity increase first and then decrease with the increase of equivalence ratio, and decrease with the increase of initial pressure. The Markstein length decreases with the increase of equivalence ratio and initial pressure. With the increase of iso-butanol blending ratio, the laminar flame burning velocity is accelerated, however, the flame tends to be unstable.