航空发动机高压转子试验模型的动力学相似设计

Dynamic Similarity Design for Experimental Model of Aero Engine High-Pressure Rotor

关键词:  航空发动机  转子系统  动力学相似  模型试验  相似准则  模型修正

Key words:  Aero engine  Rotor system  Dynamic similarity  Model test  Similarity criterion  Model updating

摘要:

为了获得能够替代航空发动机转子原型进行动力学试验的模型，提出了发动机转子系统试验模型的动力学相似设计方法。采用相似理论推导了转子系统缩比模型的动力学相似准则，继而建立缩比模型与原型的动力学相似关系。通过动力学优化方法对转子缩比模型的动力学等效模型进行修正，目标函数由固有频率、临界转速和振型组成。以双转子发动机高压转子系统的动力学相似设计为例，通过有限元仿真对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，动力学相似模型与原型的前两阶临界转速相似误差分别为3.92%和0.86%，对应振型的相关性均>0.98，且模型与原型的模态应变能分布基本一致。通过该方法获得的动力学相似模型能够较好地预测原型的动力学特性，并有效降低模型试验的成本和难度。

Abstract:

In order to obtain a model that can replace the prototype of the aero engine rotor for dynamic test， a dynamic similarity design method for the experimental model of the engine rotor system is presented. Firstly， the dynamic similarity criterions for the reduced-scale model of the rotor system were derived by similitude theory. Then， the dynamic similarity relationships between the reduced-scale model and the prototype were established. Finally， the dynamic equivalent model of the reduced-scale model of the rotor system was updated by dynamic optimization. The objective function was formulated by the natural frequencies， critical speeds and the mode shapes. Taking the dynamic similarity design for the high-pressure rotor system of the dual-rotor engine as an example， the effectiveness of the proposed method was validated by finite element simulation. Results showed that the similarity errors between the dynamic similarity model and the prototype for the first two critical speeds were respectively 3.92% and 0.86%， and the corresponding modal assurance criterion values were all above 0.98， and the distributions of the modal strain energy between the two models were in good agreement. The dynamic similarity model obtained by this method can well predict the dynamic characteristics of the prototype within the design operation speed， and effectively reduce the costs and difficulties of the model test.