摘要
针对气动激励下压缩机叶轮疲劳破坏问题,研究气动激振力的频域特性以及叶轮共振特性,提出相应的叶轮疲劳强度校核及失效分析方法。对某离心压缩机叶轮非定常气动荷载计算流体力学(Computational fluid dynamics,CFD)计算结果进行傅里叶变换,获得其频率、幅值与相位特征,重点分析气动激振荷载在相邻叶片间的相位关系。对于在相邻叶片间相位差循环对称分布的典型荷载分量,通过干涉图确定叶轮的共振模态,对于相位差非循环对称分布的非典型荷载分量,通过激振频率下叶轮动应力在各节径的分布情况确定叶轮的共振模态。基于叶轮静应力和共振动应力计算结果进行疲劳分析。结果表明,计算预测的疲劳破坏位置与实际发生疲劳裂纹位置相吻合,相位差非循环对称分布的非典型气动荷载激起叶轮零节径的共振是引起叶轮疲劳失效的主要原因。
The frequency characteristics of aerodynamic load and the resonance of compressor impeller are studied for the fatigue fallure of compressor impeller. The frequency, amplitude and phase of aerodynamic load are obtalned from the unsteady computational fluid dynamics（CFD） results of compressor impeller using fast Fourier transform（FFT）. The aerodynamic excitation phase between adjacent blades is analyzed in detall. For typical load with cyclic symmetric distribution of phase difference between adjacent blades, the interference diagram is used to determine the resonance modal. For non-typical load with non-cyclic symmetric distribution of phase difference, the resonance modal is determined by the result of dynamic stress in all nodal diameters under aerodynamic excitation frequency. Fatigue analysis is performed based on the static stress and resonance dynamic stress of impeller, which shows that the predicted fatigue position matches with the actual crack position. The zero nodal diameter resonance excited by non-typical fluid load with non-cyclic symmetric distribution of phase difference is proved to be the maln cause of impeller fatigue fallure.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2015年第9期82-89,共8页
Journal of Mechanical Engineering
基金
国家重点基础研究发展计划(973计划
2009CB724302
2015CB057301)
中央高校基本科研业务费专项资金(DUT14QY36)
辽宁省博士启动基金(20131019)资助项目
关键词
叶轮
流体激振
相位
共振
疲劳
impeller
fluid excitation
phase
resonance
fatigue
