Transient Characteristics of High-Thrust Oxygen/ Hydrogen Rocket Engine

Using the high-thrust oxygen/hydrogen rocket engine as an example, the engine transient characteristics were studied. Based on the methodologies of modular modeling and simulation, dynamic mathematical models of the engine parts were established; simulation modules of each componets of the engine system were developed; simulation analysis of the engine dynamic characteristics and test studies of start-up series were carried out. Simulation results showed that, an optimized system configuration with a gas valve set on side of the oxygen turbo to diverge 10% gas flow, the main oxidizer valve equipped with 25% first-stage position and 100% second-stage position, and a gas generator ignited when solid propellant starter operating to its 70%~80% working time, were to the benefit of the control of engine ignition mixture ratio and alse enhanced the start-up reliability. By adding a fault factor, the operational condition of the engine was decreased from 78% to 20%, while the oxidizer turbine efficiency reduced from 0.29 to 0.19, and the results of engine failure simulaiton agreed well with the ground-test data. Hence, the correctness of the model was verified, which was helpful for the analysis and location of failure. © 2021, Editorial Department of Journal of Propulsion Technology. All right reserved.