黑火药在真空环境下点火性能试验研究

黑火药作为固体火箭发动机中常用的点火药，是决定其工作性能的关键因素。为了研究黑火药在真空环境下的点火性能，通过真空点火试验，测试了不同点火结构、不同黑火药质量下的点火压力曲线和羽流现象，并与常压点火试验结果对比，分析了不同工况下黑火药点火性能的优劣。结果表明：真空环境下增加黑火药质量可以提高点火压强峰值，与常压条件相比提升幅度较小；与常压试验对比，真空下前端点火和尾部点火产生的压强峰值都会下降2MPa左右；不同黑火药质量的常压或真空点火试验中，前端点火试验样机到达压强峰值的时间都近似为5ms，而尾部点火试验样机到达峰值的时间不同；在真空点火试验中，羽流扩张角会在一段时间内变大或变小，即出现明显的黑火药不稳定燃烧现象，试验结束后有较多未燃烧完全的黑火药残留在发动机周围，而在常压点火试验中，这些未燃烧完全的黑火药颗粒会在空气中二次燃烧，黑火药残留较少。

Experimental Investigation on Ignition Performance of Black Powder in Vacuum

Abstract: As a classical ignition powder in solid rocket motor (SRM), black powder is the key factor to determine performance of SRM. To study the ignition performance of black powder in vacuum, the pressure curve and plume phenomenon of ignition under different ignition structure and different mass of black powder were obtained by the ignition test under vacuum and normal pressure. The ignition performance of black powder under different parameters were analyzed by using experimental data. Results reveal that the pressure peak will be increased as increasing mass of black powder in vacuum test, but the increment appears to be smaller relative to that in normal condition. Compared with the atmosphere test, the pressure peak generated by test prototype with forward or aft-end igniter in vacuum will drop by about 2MPa. In the atmosphere or vacuum test of different black powder mass, the time of peak pressure for test prototype with forward igniter is approximately 5ms, but the time of peak pressure for test prototype with aft-end igniter is different. In the vacuum test with different conditions, the divergence angle of plume will increase or decrease over a period of time, which is remarkable phenomenon of unstable combustion, and a lot of unburned black powder will remain around prototype after the test. while in atmosphere test, the unburned black powder will continue burning in the air, and there is a little black powder remained.