Analysis of Reliability Evaluation Method of Reusable Liquid Rocket Engine

Traditional reliability evaluation of liquid rocket engines requires a large number of verification samples. So the reliability evaluation method of reusable liquid rocket engine was studied. By analyzing the characteristics and failure modes of the instantaneous process of ignition for reusable rocket engines, and taking the instantaneous process of ignition as two independent processes (ignition process and transient development process), and the maximum entropy method and normal allowable limit method were evaluated individually. Meanwhile, the influence of reliability requirements and life shape parameters to total time of hot-fire tests, as well as the change of reliability with the number of tasks performed, were analyzed using the reliability evaluation method under study. It is shown that the proposed evaluation method can obtain higher reliability evaluation results with less test times. With the higher reliability requirements, the total time of hot-fire tests increases greatly; increasing the life shape parameters can greatly reduce the total time of hot-fire tests with the same reliability requirements; and the engine reliability decreases gradually with the increase of the number of tasks performed.