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上游静子叶片的尾迹扰动是下游转子叶片发生强迫响应问题的主要原因,但通常认为不会对颤振特性产生影响。运用CFD技术求解非定常流场,用能量法对典型涡轮风扇NASA Rotor 67进行了气动弹性分析。结果表明:不加进口导流叶片时其叶片最有可能在第二阶模态、60°叶间振动相角的情况下发生颤振;加上IGV(进口导流叶片)后,IGV的尾迹会显著改变转子叶片的颤振特性,当转子叶片的最危险颤振模态频率接近IGV尾迹的扰动频率时,即使单独转子叶片十分稳定,但在尾迹的激励下颤振仍然可能发生;当该频率远离IGV尾迹扰动频率时,尾迹扰动同样会使转子叶片气动阻尼降低。该结果意味着尽管IGV的引入不会明显改变压气机性能,但有可能会对其颤振特性带来明显的负面影响,需要在涡轮机设计中予以考虑。
The wake disturbance of upstream stator blades is the main reason for the forced response of downstream rotor blades, but it is not considered to affect the flutter characteristics. Aeroelastic analysis of a typical turbofan NASA Rotor 67 was performed using the CFD technique to solve unsteady flow fields. The results show that the flutter is most likely to occur in the absence of an inlet guide vane in the second-order mode and at a 60 ° leafy phase angle. After IGV (inlet guide vane), the wake of IGV Will significantly change the flutter characteristics of the rotor blade. When the most dangerous chatter mode frequency of the rotor blade is close to the disturbance frequency of the IGV wake, flutter may still occur under the excitation of the wake, even though the rotor blade alone is very stable. When the frequency is far away from the IGV wake disturbance frequency, the wake disturbance also reduces the rotor blade aerodynamic damping. This result means that although the introduction of IGV does not significantly change the performance of the compressor, it is likely to have a significant negative impact on the flutter characteristics that needs to be considered in the turbine design.