液体火箭发动机供应系统频率特性

为了研究减少液体火箭发动机供应系统振荡的有效工程措施，对模型系统与真实系统建立适用于中高频分析的线性化复频域传递函数矩阵模型，结合节流圈阻抗与管路特征阻抗对比方法，分析系统流路在出口压力激励下的频率特性。结果表明：激励源端可能产生谐振频率偏移效应，应选取非激励源端的幅频响应来判断系统谐振频率；节流圈具有较强的频率选择性和对表现出反谐振特征的系统具有位置选择性，需重视关注的频率与位置；节流圈位置越靠近流量振型波腹，或流量波腹位置处的节流圈压降越大，对流路中振荡衰减作用越大。针对该液体火箭发动机供应系统，缩短液氧路管长0.1 m，增大煤油路管长0.05 m，并调整节流圈压降分配，可有效减小供应系统振荡。

Frequency characteristics of liquid rocket engine feed system

In order to study effective engineering measures to reduce the oscillation in the liquid rocket engine feed system, the linearized transfer matrix models in complex domain suitable for medium and high frequency analysis were established for the model system and the real system. Combined with the method of the contrast relationship between the impedance of orifices and the characteristic impedance of pipelines, the frequency characteristic of the system flow path under the excitation of outlet pressure was analyzed. The results showed that the resonance frequency shift effect may occur at the excitation source end, and the amplitude-frequency response of the non-excitation source end should be selected to judge the system resonance frequency. The throttle orifice had strong frequency selectivity and position selectivity for the system of anti-resonance characteristics, so attention shall be paid to the frequency and location. The closer the throttle orifice to the antinode of the flow mode, or the greater the pressure drop of the throttle orifice at the position of the flow antinode, indicated the greater attenuation effect on the oscillation in the flow path. For the liquid rocket engine feed system, shortening the length of the liquid oxygen pipe by 0.1 m, increasing the length of the kerosene pipe by 0.05 m, and adjusting the pressure drop distribution of the throttle orifice can effectively reduce the oscillation of the feed system.