离心压缩机叶轮叶片疲劳断裂故障的数值分析  

Numerical Study on High Cycle Fatigue Failure of a Centrifugal Compressor Impeller Blades

作　　者：毛义军[1] 祁大同[1] 许庆余[2] 

机构地区：[1]西安交通大学能源与动力工程学院,西安710049 [2]西安交通大学航天航空学院,西安710049

出　　处：《西安交通大学学报》2008年第11期1336-1339,共4页Journal of Xi'an Jiaotong University

摘　　要：采用有限元方法计算了离心压缩机叶轮叶片的前14阶模态和离心力作用下的静应力,并采用单向流固耦合方法计算了叶轮叶片在非定常气动力载荷下的等效交变应力.为了节省计算成本,离心叶轮采用满足循环对称条件的单扇区模型.计算结果表明:非定常气动力载荷的主频率落入叶轮叶片第6阶固有频率的共振区,导致在叶轮叶片的前缘附近区域形成局部共振,使该区域的等效应力最大;离心叶轮叶片在离心力和非定常气动力共同作用下形成的交变应力小于工作条件下的屈服应力,不会形成叶片的塑性破坏,但交变载荷的长期作用导致了叶片前缘区域的高周疲劳破坏.预测的叶片应力集中位置和实际断裂位置一致,表明了该方法在工程实践中的有效性.A finite element analysis（FEA） method was adopted to calculate the modes and static stress generated from centrifugal force of the impeller blades and a unidirectional coupled fluidstructure interaction method was applied to analyze the forced vibration of the impeller blade on excitation of the unsteady aerodynamic loads. In order to save the computational cost, the centrifugal impeller was modeled as a single sector based on the cycle symmetry assumption. The result shows that the insufficient margin between the dominant frequency of unsteady aerodynamic loads and the 6th natural frequency of the impeller blade results in local resonance vibration at the leading edge of the impeller blade. Although the equivalent stress is lower than the yield stress of steel, the high cycle fatigue （HCF） failure of the impeller blade may be caused by the long-term excitation of the unsteady aerodynamic loads. The predicted stress concentration region of the impeller blades is in accordance with the actual crack location.

关 键 词：离心压缩机 故障 交变应力 高周疲劳 数值分析 

分 类 号：TB302.3[一般工业技术—材料科学与工程] O346[理学—固体力学]