Analysis of dynamic characteristics and sensitivity of hydrogen-oxygen expansion cycle rocket engine system

The success of the launch mission depends on the dynamic characteristics of the rocket engine system, while the engine development process is based on the parameter sensitivity analysis. However, the dynamic characteristics and parameter sensitivity of the hydrogen-oxygen expansion cycle engine remain unclear. This research built the simulation model of basic components and overall system of the hydrogen-oxygen expansion cycle engine. A 3-factor and 9-level numerical simulation study was carried out based on the structural parameters of the cooling channel. Results show that at 0.1s after the ignition of the engine, the speed of oxygen pump drops by 16.4%, while the torque of the hydrogen turbine drops by 43.6%. The rise of coolant temperature between the inlet of the cooling channel and the outlet of combustion chamber is about 185 K, which is about 4 times of that between the outlet of combustion chamber and the first section outlet of the nozzle. The sensitivity of the response time to the rib height reaches 0.36, while the sensitivity of response time to the rib width and the nozzle wall thickness are 0.15 and 0.12, respectively. These findings contribute to the start-up analysis and design of the hydrogen-oxygen expansion cycle engine.