固体发动机点火适应性试验及其低温下药柱内孔应变分析

Firing test of solid rocket motor suitability and strain analysis around its grain bore under low temperature

为了深入研究壳体材料、推进剂配方、药柱m数、初始温度等因素对丁羟类推进剂固体火箭发动机的整机可靠性结果的影响,进行了多台钢壳体和碳纤维壳体发动机在-40、20、60℃下的地面点火验证试验。试验发现,该类发动机在-40℃低温下点火易发生失效,且失效多发生在点火信号发出后的压强上升阶段。为此,对各发动机低温点火下的药柱内孔点火应变速率进行了计算。结果表明,失效的主要原因是推进剂低温延伸率偏低,难以适应点火增压过程引起的高应变条件。

In order to deeply study the influence of case material,propellant formula,grain m number(the ratio of outer diameter to inner diameter),initial temperature and other factors on the test reliability of HTPB propellant-type solid rocket motor,several metal case-and carbon fiber case-made motors'verification firing tests were performed at different temperatures,-40℃,20℃and 60℃,and it is found that this type of motor is prone to failure when ignited at a low temperature of-40℃,and the failure mostly occurs in the pressure-rise stage after the ignition signal is sent out.Then the strain rate around the grain bore for each motor under low temperature ignition was calculated.The results show that the main reason for the failure is that the low temperature elongation of the propellant is too low to adapt to the high strain conditions induced in the ignition pressurization process.