重复使用液体火箭发动机可用度的数字仿真

重复使用液体火箭发动机(RLRE)可以降低航天发射成本,是未来航天运载器的发展方向之一.RLRE的复杂性、部件寿命模型的差异等不确定因素使得它的可用度评估工作十分困难.在现有的航天飞机使用资料的基础上,利用蒙特卡罗数字仿真方法,以航天飞机主发动机(SSME)高压液氢涡轮泵(HPFTP)为例对其可用度进行了分析.该方法不涉及部件的寿命分布模型,但考虑了前期维修对后期故障的影响,可以合理地模拟系统的故障发生过程.结果表明,在基本维修的情况下,HPFTP存在最佳的预防维修周期,其平均最佳合理预防维修周期为6 340 s,为满足航天飞机的任务需求,理论上预防维修前可重复使用12次,对应的平均最佳可用度为0.285.较低的可用度反映了HPFTP工作过程的特殊性.本文方法可以为航空航天推进系统可重复使用性研究提供参考.

Digital simulation on reusable liquid rocket engine availability

The reusable liquid rocket engine (RLRE), which can reduce the space launch cost, is one of the future spacecraft development directions. It is difficult to assess the RLRE availability for its complexity, differences of the component life model and other uncertain factors. As an example, the availability of space shuttle main engine (SSME) high-pressure fuel (hydrogen) Turbopump (HPFTP) was analyzed using Monte Carlo simulation technology based on the historical data of SSME. The method, taking into account the impact of early maintenance on the later maintenance, did not involve the life distribution model of components, and can reasonably simulate the process of system failure occurrence. The results show that under incomplete maintenance the mean best reasonable preventive maintenance time of HPFTP is 6 340 s, it can be reused theoretically 12 times for satisfying the mission requirement of the space shuttle, and the corresponding mean best availability is 0.285. The availability of HPFTP is low due to its severe working process. This study provides a reference for studying the aerospace propulsion reusability.