火箭推进

采用分段集中参数的有限元方法建立了发动机模块化模型,以此模型搭建了燃气发生器循环液体火箭发动机仿真模型,对变推力发动机在变工况下的系统特征及频率响应进行了研究。研究表明:发动机系统在变工况后系统特征频率及其对应的阻尼系数有明显变化。通过提取变工况过程中的主要频率,发现对应能量峰值的频率为5.34 Hz。在发动机系统工况转换过程中,输入带有该频率的扰动的入口压力信号,仿真结果证明这种低频扰动使系统稳定裕度降低,应当避免该频率下扰动信号出现。

A gas generatorcycle liquid rocket engine simulation model was established based on module built on the finite element method of the segmentation concentration parameter.The system characteristics and frequency response of variable thrust engine under variable working conditions were studied.The results indicater:the engine system has different system characteristic frequencies with their corresponding damping coefficient under different operating conditions.By extracting main frequencies during the variable operating conditions, the frequency corresponding to peak energy was found to be 5.34 Hz.During the transition from high operating condition to low operating condition, the inlet disturbing pressure signal with frequency mentioned above was input,the simulation results show that this low frequency disturbance reduces the stability margin of the system and the occurrence of disturbance signals at this frequency should be avoided.

引言
1 发动机主要组件建模
2 结果与讨论
3 结论

图1 泵压式燃气发生器循环发动机系统示意图<br/>Fig.1 Schematic diagram of gas generator cycle engine system

图1 泵压式燃气发生器循环发动机系统示意图
Fig.1 Schematic diagram of gas generator cycle engine system

表1 设置工况说明<br/>Tab.1 Description of operating condition 单位:kg/s

表1 设置工况说明
Tab.1 Description of operating condition 单位:kg/s

图2 推力室室压随时间变化曲线<br/>Fig.2 Thrust chamber pressure vs time

图2 推力室室压随时间变化曲线
Fig.2 Thrust chamber pressure vs time

图3 离心泵转速随时间变化曲线<br/>Fig.3 Centrifugal pump speed vs time

图3 离心泵转速随时间变化曲线
Fig.3 Centrifugal pump speed vs time

图4 涡轮功率随时间变化曲线<br/>Fig.4 Turbine power vs time

图4 涡轮功率随时间变化曲线
Fig.4 Turbine power vs time

表2 高工况系统阻尼系数及频率<br/>Tab.2 Eigenvalues and frequency of system at high operating condition

表2 高工况系统阻尼系数及频率
Tab.2 Eigenvalues and frequency of system at high operating condition

表3 低工况系统阻尼系数及频率<br/>Tab.3 Eigenvalues and frequency of system at low operating condition

表3 低工况系统阻尼系数及频率
Tab.3 Eigenvalues and frequency of system at low operating condition

图5 变推力过程室压FFT分析<br/>Fig.5 FFT analysis of chamber pressure of thrust varying process

图5 变推力过程室压FFT分析
Fig.5 FFT analysis of chamber pressure of thrust varying process

图6 4.01 s推力室压力的Nyquist曲线<br/>Fig.6 Nyquist curve of thrust chamber pressure at 4.01 s

图6 4.01 s推力室压力的Nyquist曲线
Fig.6 Nyquist curve of thrust chamber pressure at 4.01 s

图7 4.02 s推力室压力的Nyquist图<br/>Fig.7 Nyquist curve of thrust chamber pressure at 4.02 s

图7 4.02 s推力室压力的Nyquist图
Fig.7 Nyquist curve of thrust chamber pressure at 4.02 s

图8 4.03 s推力室压力的Nyquist图<br/>Fig.8 Nyquist curve of thrust chamber pressure at 4.03 s

图8 4.03 s推力室压力的Nyquist图
Fig.8 Nyquist curve of thrust chamber pressure at 4.03 s

图9 4.04 s推力室压力的Nyquist图<br/>Fig.9 Nyquist curve of thrust chamber pressure at 4.04 s

图9 4.04 s推力室压力的Nyquist图
Fig.9 Nyquist curve of thrust chamber pressure at 4.04 s

图10 4.05 s推力室压力的Nyquist图<br/>Fig.10 Nyquist curve of thrust chamber pressure at 4.05 s

图10 4.05 s推力室压力的Nyquist图
Fig.10 Nyquist curve of thrust chamber pressure at 4.05 s

表4 各观测点稳定裕度<br/>Tab.4 Stability margin of each observation point

表4 各观测点稳定裕度
Tab.4 Stability margin of each observation point

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[5] 李斌, 张小平, 高玉闪.我国可重复使用液体火箭发动机发展的思考[J].火箭推进, 2017, 43(1):1-7.

备注

引言

1 发动机主要组件建模

2 结果与讨论

3 结论

期刊信息