含拉杆裂纹的组合转子性能退化机理

摘要

The degradation of combined rotor,as the core part of gas turbine,has great effect on gas turbine's performance.Crack of the rod is one of the main reasons which cause performance degradation of combined rotor,while few relevant study has been reported at present.In order to get combined rotor's bending natural frequency variation with time,dynamic features of combined rotor with cracked rod was analyzed considering interface contact effect.By describing degradation path of cracked rotor through defining degradation degree parameters,performance degradation quantitative evaluation of combined rotor was realized.In order to get the degradation characteristics of combined rotor,unbalance response analysis of combined rotor in different degradation degree was conducted,and the results verify the theoretical analysis at the same time.The results show that the degradation of combined rotor is extremely slow in the stable degradation stage,the significant transition point which leads to fault occurs when the degradation reaches a certain extent,and the number of rods and disks and the position of crack in the rod have great influence on the degradation of combined rotor.The results provide theoretical reference for structure design of combined rotor and determining the damage location of rotor rod.%考虑含拉杆裂纹的组合转子接触界面并对其进行动力学分析,得到组合转子弯曲固有频率随时间变化规律;通过定义退化量参数,描述裂纹转子的退化轨迹,实现其性能退化的定量评估;针对不同退化程度的组合转子进行不平衡响应分析,得到组合转子的退化特征,同时对理论分析进行一定的实验验证.研究结果表明:在稳定退化阶段,组合转子的性能退化极为缓慢,退化达到一定程度时有明显通向故障的转捩点;且不同数目的拉杆、轮盘级数以及裂纹出现在拉杆不同位置时对组合转子退化速率有较大的影响.研究结论为组合转子结构设计及确定转子拉杆裂纹损伤位置等提供理论参考依据.