ICOPE-15-C054 Nonlinear vibration characteristic research of the vane row in an axis-flow compressor

抄録

Vane failure due to resonance vibration should be avoided in an axis-flow compressor design. So the vibration characteristic of the vane row should be analyzed. The interaction of adjacent blades and vanes causes unsteady flow. Once the margin between the vane natural frequency and the aerodynamic force frequency is insufficient, it will lead excessive vibration stress on the vane. As the vane is assembled as clearance fit, its contact boundary is nonlinear. This paper introduces the equivalent stiffness matrix into the finite element model to calculate a series of equivalent linear vibration system characteristic. For each linear vibration system, the natural frequency of the fundamental modal shape is analyzed. Then the curve of natural frequency to the equivalent contact stiffness can be drawn. A vane modal test fixture is designed to complete the modal identification. Combining the series of modal simulation and test, the natural frequency dispersion of the vane nonlinear vibration system can be predicted. Strain gauge is used to test the vane dynamic stress during the compressor mapping test. The vibration characteristic in the operating condition is compared with the predicted model. The equivalent contact stiffness of the vane in the operating condition can be verified. The results show that the predicting model can be used to analyze the nonlinear vibration characteristic of the vane.