偏二甲肼液滴燃烧特性及影响因素实验研究

Experimental study on combustion characteristics of UDMH droplet and influence factors on combustion

设计了一套密闭环境液滴燃烧实验系统,开展了不同实验工况下偏二甲肼(UDMH)液滴在四氧化二氮(NTO)环境中的着火燃烧实验,详细分析了UDMH单液滴着火燃烧特性,考察了燃烧室温度、压力、液滴初始直径及速度对燃烧过程的影响。结果表明,液滴燃烧经历了初始燃烧阶段,剧烈燃烧阶段和熄燃阶段3个过程。其中,初始燃烧阶段和熄燃阶段的持续时间均较长。燃烧过程中,燃烧火焰呈现出明显的双火焰峰结构,内层为规则的椭圆形分解火焰峰,外层为带有尾迹火焰的扩散火焰峰。增加燃烧室温度促使液滴表面与内部的燃料快速蒸发,形成了充足的燃料蒸气环境,有助于液滴的着火燃烧;燃烧室压力的增加加快了反应速度,减少了液滴生存时间;增大液滴下落速度导致液滴表面蒸发流率得到增强,更易产生足够的燃料蒸气,促进燃烧的进行,从而有助于液滴生存时间的减小。

An integrated experiment system used for single droplet combustion of hypergolic propellant was established.The experiments of UDMH droplet burning in dinitrogen tetroxide were carried out in different temperature and pressure conditions.The combustion characteristics of UDMH single droplet are analyzed.The effects of chamber temperature,pressure,initial diameter of droplet and velocity on combustion process are investigated carefully.The results show that the combustion process of droplets has experienced three periods,initial combustion period,intense combustion period and extinct combustion period.In the burning process,the combustion flame displays double flame front structure obviously,the inner is the decomposed flame front and the outer is the diffused flame front with wake flame.Increasing the chamber temperature or pressure,or enhancing the velocity of droplet,can improve the combustion rate of hypergolic propellant,and decrease the lifetime of droplet.