火箭发动机贮箱振动特性分析

为了研究某发动机充液和空载2种工况下贮箱的振动特性，利用流固耦合理论计算了2种工况下贮箱的模态和频率响应。结果表明：在充液工况下，各阶湿模态频率是空载时候干模态的0．5倍；在5—800Hz的激振条件下，空载工况下贮箱在第4阶模态处与外界振动激励发生共振；充液工况下贮箱在第3阶模态处与外界振动激励发生共振，空载状态下贮箱的频率响应的位移最大值为1×10mm，充液状态下贮箱频率响应的位移最大值为1×10^-57mm；充液使贮箱振幅减小，但使贮箱更容易与外界发生共振。

Analysis of Vibration Characteristic of Propellant Tank of Liquid Rocket Engine

Liquid-so.lid coupling theory was used to calculate vibration response and modals of propellant tank of rocket engine under empty and filled conditions. The results showed that the wet modal frequency of the tank is 0.5 times high as it was empty when it was filled with liquid. Under the frequency range of 5 Hz to 800 Hz exciting force, the propellant tank sympathetic vibration was on its 4th modal when it was empty and on its 3rd modal when it was filled with liquid. Its response maximum displacement was 1×10^-5 mm when the propellant tank was empty and the response maximum displacement was 1×10^-57mm when it was filled with liquid;liquid filling reduced the tank amplitude of vibration, but it made the tank tend to sympathetic vibration.