气驱预压涡轮泵对发动机液氧路频率特性影响

液氧/煤油补燃循环发动机液氧路频率特性对于火箭POGO振动和发动机动力学特性具有重要的意义。以某型液氧/煤油补燃循环发动机氧路流体系统为研究对象,重点考虑气涡轮和泵动态特性的影响建立了系统线性化小偏差频域模型。应用复系数状态空间矩阵法计算了气涡轮压比、氧预压泵动态增益、燃气掺混段特性对系统频率特性的影响。研究结果表明:预压涡轮低压比状态下,系统响应幅值变大,预压涡轮压比对系统频率影响较小;预压泵动态增益越大,系统频率越低,幅值越大;燃气掺混段长度越大,系统频率越低,幅值越小。

Influence of gas drive pre-pressurized turbo-pump on frequency characteristics of liquid oxygen system in rocket engine

The frequency characteristics of liquid oxygen system in the LOX/kerosene staged combustion cycle engine are of great significance to the vibration of rocket POGO and the engine dynamics.Based on the liquid oxygen system in a LOX/kerosene staged combustion cycle engine,a linearized small deviation frequency domain model was established by emphatically considering the influence of gas turbine and pump dynamic characteristics.The influence of the gas turbine pressure ratio,the dynamic gain of the oxygen pre-pressurized pump and the gas mixing section on the system frequency characteristics were calculated by using the complex coefficient state space matrix.The results show that under the low-pressure ratio condition of the preloaded turbine,the system response amplitude becomes larger,which has less influence on the system frequency.The higher the dynamic gain of the pressurized pump,the lower the system frequency and the larger the amplitude.The longer the gas mixing section,the lower the system frequency and the smaller the amplitude.