SYSTEM FREQUENCY CHARACTERISTIC ANALYSIS FOR A LARGE-THRUST LOX/KEROSENE STAGED COMBUSTION CYCLE ENGINE

摘要

The LOX/kerosene staged combustion cycle rocket engine is one of the major propulsion devices for new generation launch vehicles. Study of frequency characteristic has become one of the key technologies in dynamic characteristic research of engine system and POGO stability analysis of liquid rocket. The linear small deviation non-dimensional dynamic transfer matrix model of the engine system is developed by modularization and topology generation modeling method. Based on transfer function, the frequency characteristic of the engine system is investigated. The results show that: 1) The characteristic of wide passing frequency band and large phase lag of staged combustion cycle engine are validated. 2) The dynamic characteristic of engine system can be improved by installing a flow regulator in the gas generator fuel path. 3) The oxidizer pump parameters and the flow regulator have important influence on the frequency characteristic of the system. 4) The rotation speed fluctuation of turbopump has little influence on the low-frequency dynamic characteristic of engine, and the influence of pressure and flow fluctuation at the engine inlet on the turbo-pump speed pulsation can be neglected.