CAJ | 학술논문

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。
침대기동격려하압축궤협륜피로파배문제，연구기동격진력적빈역특성이급협륜공진특성，제출상응적협륜피로강도교핵급실효분석방법。대모리심압축궤협륜비정상기동하재계산류체역학(Computational fluid dynamics, CFD)계산결과진행부리협변환，획득기빈솔、폭치여상위특정，중점분석기동격진하재재상린협편간적상위관계。대우재상린협편간상위차순배대칭분포적전형하재분량，통과간섭도학정협륜적공진모태，대우상위차비순배대칭분포적비전형하재분량，통과격진빈솔하협륜동응력재각절경적분포정황학정협륜적공진모태。기우협륜정응력화공진동응력계산결과진행피로분석。결과표명，계산예측적피로파배위치여실제발생피로렬문위치상문합，상위차비순배대칭분포적비전형기동하재격기협륜령절경적공진시인기협륜피로실효적주요원인。
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.