航空发动机低压转子系统的动力学相似设计方法

提出了航空发动机转子系统动力学相似设计方法,以便采用模型替代实际结构对其动力学特性进行研究。基于转子系统的动力学等效原则,通过动力学优化方法建立全尺寸原型的相似等效模型。综合采用方程分析和量纲分析推导转子系统的动力学相似准则,并根据转子设计参数的相似关系建立相似等效模型的缩比模型。基于模型修正方法对三维设计模型的相似误差进行修正,得到预测精度较高的动力学相似模型。以双转子发动机低压转子试验模型的动力学相似设计为例,通过有限元仿真对动力学相似设计方法的有效性进行了验证。结果表明:在设计转速范围内,通过该方法得到的动力学相似模型能够有效预测全尺寸原型的临界转速和不平衡响应,前三阶临界转速的相似误差分别为3.09%、1.75%和0.31%,对应振型的相关性均大于0.93。该方法具有较高的实用价值,可为发动机整机动力学相似设计提供参考。

Dynamic similarity design method for aero-engine, low-pressure rotor system

Dynamic similarity design of an aero-engine rotor system was presented to study its dynamic characteristics using the design model instead of the real structural system. Firstly, the similar equivalent model of the rotor full scale prototype, based on the dynamic equivalence principle of the rotor system, was established by dynamic optimization. Then, the dynamic similarity criterions of the rotor system were derived by equation analysis combined with dimensional analysis, and the reduced-scale model of the similar equivalent model was constructed according to the similarity relations of the rotor design parameters. Finally, using the model updating method, the dynamic similarity model of high prediction accuracy was obtained by updating the similarity error of the three-dimensional design model. Taking the dynamic similarity design for the low-pressure rotor of the dual-rotor aero-engine as an example, the effectiveness of the dynamic similarity design method was validated by finite element simulation. Results showed that the dynamic similarity model obtained by this method could effectively predict the critical speeds and unbalance responses of the full scale prototype within the design operation speed. The similarity errors for the first three critical speeds were 3.09%, 1.75% and 0.31%, respectively, and the corresponding modal assurance criterion values were all above 0.93. This method has great value for practical application, and provides a reference for dynamic similarity design of the whole aero-engine.