支承结构参与振动对涡轮泵转子动特性的影响

Effects of Vibration of Supporting Structure on Dynamic Characteristics of a Turbopump Rotor

关键词:  液体火箭发动机  涡轮泵  转子动力学  临界转速  弹性支承  动刚度

Key words:  Liquid rocket engine  Turbopump  Rotordynamics  Critical speed  Flexible support  Dynamic stiffness

摘要:

针对采用弹性支承结构的高转速涡轮泵转子，建立了考虑支承结构参与振动的转子系统有限元模型，并对模型和计算方法的正确性进行了验证；以某涡轮泵转子为对象，采用三种不同的支承结构模型，计算分析了支承结构模型的差异，以及参与振动的支承结构质量对临界转速和模态振型的影响，并将临界转速计算和试验结果进行了对比分析。结果表明：支承结构的建模方法和参与振动的质量都对转子动特性有较大影响；支承结构参与振动会使转子支承动刚度相比静刚度明显降低，其中二阶临界转速下的动刚度相比静刚度降低达20.6%；考虑支承结构参振的转子动力学模型可将临界转速计算误差由8%降低至2%左右。

Abstract:

This paper concerns the rotordynamic characteristics of high-speed turbopump rotors with flexible supports. The finite element model of the rotor system considering the vibration of the supporting structure was presented. The correctness of the model and calculation method was verified. The influence of the models and vibration mass of supporting structure on the critical speeds and mode shapes of a turbopump rotor was calculated and analyzed using three different supporting structure models. The calculated critical speeds were also compared with test results. The results show that both the modeling method and vibration mass of the supporting structure have great influence on the dynamic characteristics of the rotor. The vibration of the supporting structure could greatly weaken the dynamic supporting stiffness for the rotor， for example， the dynamic supporting stiffness at the 2nd critical speed is 20.6% less than the static stiffness. The rotordynamic model considering the vibration of the supporting structure could reduce the calculation errors of rotor critical speeds from 8% to 2%.