重复使用液体火箭发动机涡轮泵安全寿命预估方法

Predicting method of safety life of reusable liquid rocket engine turbopump

利用复杂系统寿命分布模型和故障树分析(FTA)理论建立了涡轮泵的安全寿命预估方法,并以航天飞机主发动机(SSME)高压液氢涡轮泵(HPFTP)的安全寿命预估为例,对该方法进行了说明。研究结果表明:①当待考核的HPFTP关键部件数大于10时,其寿命模型可以用指数分布近似表示,数目越多近似结果越可靠;②HPFTP的平均无故障工作时间(MTBF)为76917 h,平均维修时间(MTTR)为8879 h,0.9988可靠度对应的安全寿命为25575 s,可安全使用49次;0.9996可靠度对应的安全寿命为8521 s,可安全使用16次;安全使用11次对应的可靠度为0.9997;③HPFTP涡轮叶片和喷嘴对应的关键重要度分别是0.2175和0.2166,集液器和叶轮对应的关键重要度都是0.1742。该研究方法可为液体火箭发动机涡轮泵等复杂组件可重复使用性研究提供一定的参考。

Based on the life distribution model of complex system and fault tree analysis(FTA)theory, a safety life prediction method of turbopump was established. As an example,the safety life of the high pressure liquid hydrogen turbopump(HPFTP)of the space shuttle main engine(SSME)was verified to demonstrate this method. The results showed that:(1)The life of complex system roughly followed the exponential distribution when the number of HPFTP critical components was more than 10,and a more reliable result accompanied a larger number.(2)The mean time between failure(MTBF) and mean time to repairment(MTTR)of HPFTP was76 917 h and 8 879 h, respectively, and the safety life of 0. 998 8 reliability was 25 575 s,which can be used 49 times safely;the safety life of 0. 999 6 reliability was 8 521 s, which can be used for 16 times;the reliability was 0. 999 7 for 11 times safety use.(3)The key components of HPFTP safety life were turbine blade and nozzle,and their corresponding critical importance was 0. 217 5 and 0. 216 6,respectively,and the critical importance of both liquid collector and the impeller was 0. 174 2. This work can provide a reference for the reusability research of complex components such as liquid rocket engine turbopump.