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在轴流式压气机和涡轮中,不均匀导向叶栅及其尾迹将引起栅后流场速度和总压的周向畸变,并对其后的转子叶片产生周期性激振。本文分析了多种不均匀叶栅及其尾迹引起叶片振动的机理,并推导了计算叶栅尾迹、气体激振力以及叶片振动响应的计算方法。最后,对几种具体的不均匀叶栅进行了计算,并与相应的均匀叶栅进行了比较。结果表明:不均匀导流叶栅及其尾迹所引起的流场周向畸变,不仅使气体激振力频带变宽,而且还可能产生幅值很大的低阶倍频谐振力,并导致转子叶片疲劳破坏。
In axial compressors and turbines, the non-uniform guide vanes and their wake will cause the circumferential flow field velocity and the total pressure of the circumferential distortion, and the subsequent rotor blades produce periodic excitation. In this paper, the mechanism of vane vibration caused by many kinds of non-uniform cascades and their wake is analyzed, and the calculation method of calculating blade wake, gas exciting force and vane vibration response is deduced. Finally, several specific non-uniform cascades were calculated and compared with the corresponding uniform cascades. The results show that the circumferential distortion of flow field caused by unevenly distributed guide vanes and their wake can not only broaden the gas excitation frequency band, but also generate large-amplitude low-order harmonic resonance and lead to rotor Blade fatigue damage.