煤油凝胶单液滴燃烧特性试验

利用二氧化碳激光器点火装置及高分辨率高速成像系统,开展了煤油凝胶单液滴在空气中的点火燃烧试验,观察了凝胶液滴在燃烧过程中的形态变化,为进行凝胶冲压发动机的总体设计提供依据。试验结果表明,煤油凝胶液滴的燃烧经历了煤油的蒸发燃烧、气泡产生、胶凝层形成、胶凝层破裂、微爆等物理化学过程,基本满足D²定律。分析了胶凝剂含量、硼含量对含硼煤油凝胶燃烧过程的影响。当硼含量一定时,随着胶凝剂含量的增加,含硼凝胶的稳定燃烧相对时间增加,但微爆过程更加剧烈;当胶凝剂含量一定时,随着硼含量的增加,含硼凝胶液滴的稳定燃烧相对时间缩短,微爆现象更加剧烈。

Experimental study on ignition and combustion characteristics of single kerosene gel droplet

CO₂ laser ignition and combustion setup is designed, and a series of experiments of single kerosen gel droplet ignition and combustion is conducted, with the help of a high resolution and high speed image formation system. During the ignition and combustion, the structure of single gel droplet is observed directly and clearly. The results indicate that the process of ignition and combustion of a single gel droplet includes:the evaporation and combustion of kerosene droplet, bubbles occurence, gellant layer occurence, diruption of gellant layer, and microexplo-sion of droplet, which basically follows the D² law. Then we compared the differences of varied percentages of gellant and boron particles. We found that the steady combustion process tend to be relatively longer when increasing the percentage of gellant, but the microexplosion would be more active, the steady combustion process tend to be shorter when increasing the percentage of boron particles, and the microexplosion also tends to be more active also.