关键词: 液体火箭发动机;流量调节器;管路系统;瞬态过程;自激振荡;频率特性

Abstract: Low-frequency auto oscillation occurs in the pipeline system of flow regulator under the condition of small flow and large pressure drop. In order to deeply understand the mechanism of auto oscillation， a numerical simulation study was carried out based on the dynamic model of spring oscillator of flow regulator in combination with a certain output-flow-stabilized regulator and pipeline system. The numerical simulation results show that the auto oscillation frequency is 94 Hz， which is consistent with the engine test results. The influence of flow regulator structure parameters on the stability of the system was analyzed. The triangular slide valve throttle can suppress the auto oscillation of the pipeline system. The mechanism of auto oscillation is hydrodynamic oscillation with the throttling interface of the slide valve， and it forms a positive feedback effect on the pipeline system. When the comprehensive stiffness coefficient of the flow regulator is less than zero， the pipeline system will be unstable and oscillate. The load characteristic test of a certain flow regulator shows that the stability of pipeline system becomes worse as the pressure drop of flow regulator increases. The amplitude-frequency characteristic and stability boundary obtained by simulation are consistent with the test results.

Key words: Liquid rocket engine;Flow regulator;Pipe system;Transient process;Auto oscillation;Frequency characteristics