氧气/煤油点火装置高空点火试验研究

为了实现冲压发动机高空环境条件下可靠点火以及空中熄火后再次点火的需求,研制了一种可多次点火、重复使用的氧气/煤油点火装置,并对氧气/煤油点火装置的高空点火性能进行了试验研究。试验结果表明：高空环境条件下温度和压力发生了变化,着火边界变窄,点火可靠性较地面降低,通过进一步理论分析,认为降低油气比和改变点火时序是提高高空点火可靠性的关键所在。适当降低煤油流量的供应将降低油气比,从而可以将设计点控制在着火区,点火装置时序设计按电嘴发火一氧气进入预燃室一煤油进入预燃室的顺序执行,该时序设计可以确保点火初期让油气比经历从贫油状态过渡到富油状态,当进入着火区时即能保证点火成功。

High-altitude ignition tests of oxygen/kerosene ignition system

In order to accomplish reliable ignition and re-ignition ot scramjet, an uxygen/kerosene ignition system, which can ignite for several times and can be used repeatedly, was developed. The ignition performance test of the system was performed in high altitude environment. The results indicate that the flame boundary narrows down and the ignition reliability is lower than that on ground due to temperature and pressure change at high altitude. Theoretical analysis shows that the effective way to improve the ignition reliability at high altitude is to decrease the kerosene/oxygen ratio and change the ignition sequence. Proper reduction of kerosene flow can reduce the kerosene/oxygen ratio, thus the design point can be kept in the fire area. The time-sequence of the ignition system can be designed as spark plug ignition, oxygen entering and kerosene flow into the pre-combustion chamber. The sequence can ensure that the kerosene/oxygen ratio in ignition stage transits from the deficient oil state to the rich oil state to ensure successful ignition when kerosene and oxygen enter into fire area.