带柔性静子结构高速转子支承刚度修正方法

针对某涡轴发动机带柔性过渡段悬臂动力涡轮转子支承刚度的修正方法开展研究。以动力涡轮模拟转子为研究对象,建立了转子的有限元分析模型,基于SAMCEF分析软件计算得到了转子的前三阶临界转速和振型,在高速旋转试验器上完成了全转速范围内的动力特性试验,分析确认了柔性过渡段是导致模拟转子前两阶临界转速存在较大计算误差的主要原因,基于临界转速试验结果,提出了一种转子支承刚度的修正方法并对模拟转子的支承刚度进行了修正,推算得到了柔性过渡段的横向刚度。其次,以真实动力涡轮转子为研究对象,按修正方法对真实动力涡轮转子的支承刚度进行了修正,支承刚度修正后其前两阶临界转速的计算误差大幅减小,验证了该修正方法的正确性,修正后的计算模型很好地反映了真实转子的实际情况。研究工作对类似高速转子支承刚度的修正有重要的指导意义,可有效提高航空发动机带柔性静子结构高速柔性转子的建模精度。

Support stiffness modification method for a high-speed rotor with flexible stator

A support stiffness modification method for a cantilever power turbine rotor of a turbine shaft engine with flexible transition section was studied. Firstly，a power turbine simulated rotor was taken as the study object to establish its finite element analysis model. The rotor’s first three critical rotating speeds and modal shapes were computed based on the software SAMCEF, and the rotor’s dynamic characteristics tests within the full rotating speed range were completed on a high-speed rotating test rig. The test results showed that the flexible transition section is the main reason to cause big calculation errors of the rotor’s first two critical rotating speeds. Based on critical rotating speed test results, a method for rotor support stiffness modification was proposed to modify the simulated rotor’s support stiffness, and obtain the flexible transition section’s lateral support stiffness through reckoning. Secondly, an actual power turbine rotor was taken as the study object, its support stiffness was modified according to the proposed method. After modification, the actual rotor first two critical rotating speeds’ computation errors were considerably reduced to verify the correctness of the proposed method. It was shown that the modified computation model can reflect the practical situation of the actual rotor; the study results can provide a guide for modifying similar high-speed rotor’s support stiffness, and effectively improve modeling precision of high-speed flexible rotors of aero-engines with flexible stator. 