流固耦合下轴流压气机叶片振动特性数值研究

气流扰动触发的叶片振动是导致叶片疲劳失效的主要原因,针对此问题,首先,建立叶片流固耦合时域计算模型,研究叶片振动特性,并进行叶片失效分析;其次,建立压气机叶片振动分析模型,结合叶片振动试验来验证模型的有效性;然后,考虑气体与叶片的耦合作用,通过数值仿真模拟得到典型工况下的叶片表面气动载荷,并将其引入旋转叶片有限元振动分析模型进行叶片振动响应计算;最后,引入坎贝尔图确定叶片危险工况,得到危险工况下的叶片动应力分布,并进行叶片疲劳失效分析。结果表明:临界工况下叶片振动应力分布与发生共振的模态振型密切相关;临界转速下叶片发生的1阶共振是造成叶片失效的主因。

Numerical Study on Vibration Characteristics of Axial Flow Compressor Blade Under Fluid-Structure Interaction

The vibration triggered by airflow disturbance is the main reason of compressor blade fatigue failure. Therefore, in this paper, a time domain calculation model of fluid-structure interaction is established to study on the vibration characteristics and to carry out failure analysis of the compressor blade. On the basis of modal test, the vibration analysis model of blade is established and verified by a finite element method. Considering the coupling effect of the gas and the blade, computational fluent dynamics is employed to compute the aerodynamic load on the blade surface under some rated conditions, which is imported to blade vibration analysis model to carry out vibration response analysis. Finally, the blade dangerous working conditions are determined through Campbell diagram, and the blade dynamic stress distribution of these working speeds is to carrying out the blade fatigue failure analysis. The result shows that the peak vibration stress distribution is closely related to the modal shape of the blade. The first order resonance of the blade at the critical speed is the main cause of the blade fatigue failure.