航空发动机风扇叶片与机匣刮蹭分析及结构设计

针对异常载荷下,航空发动机宽弦风扇叶片的叶尖与机匣刮蹭变形及损伤特征缺乏数据支持,而传统理论计算方法存在较大的误差问题，建立了宽弦风扇叶片叶尖刮蹭显式动力学分析模型,采用宽弦风扇叶片与机匣刮蹭试验数据,对分析模型的计算精度进行了验证。基于分析模型进行了仿真参数的敏感度分析,得到了叶片与机匣刮蹭后叶片变形及机匣损伤规律。研究结果表明:叶尖伸长量对转子转速非常敏感，叶尖径向伸长量增加速率远大于转速增加值，因此在叶片设计中应考虑到风扇叶片极限转速下叶尖伸长量。同时需要选取合理的扭转角度以满足叶片安全性和气动性能的要求。在风扇机匣包容区设计中应主动考虑异常载荷的影响，增大安全性设计域度；设计合理的耐磨层材料参数，减小风扇叶片对其冲击损伤。采用该方法可以提高叶尖间隙控制精度,减小刮蹭对叶片和机匣造成的损伤。 

Rubbing analysis and structural design for fan blade and case of aero-engine

Under abnormal loads, there is often a lack of data to describe the rubbing deformation and damage characteristics between the blade tip and the case of the wide-chord fan blade of aero-engines. The traditional theoretical calculation methods have large errors. To solve this problem, an explicit dynamic analytical model for the blade tip rubbing of a wide-chord fan was established. The calculation accuracy of the analytical model was verified by utilizing the test data of wide-chord fan blades and case. Based on the analytical model, sensitivity analysis of simulation parameters were carried out. The rules of blade deformation and case damage after the rubbing of the blade and case were obtained. The results indicate that the blade tip elongation is sensitive to rotor speed,and the increase rate of blade tip elongation is much bigger than the rotor speed.So the blade tip elongation at limited fan blade speed was considered in design. Suitable twist angle is an important factor of safe and dynamic performance demand.In the case inclusive area design, it is necessary to enlarge the safe margin to eliminate the influence of abnormal load. Choosing wear-resistant material with reasonable parameter is helpful to reduce the impact damage from fan blade. The proposed method can improve the accuracy of tip clearance control, and reduce the risk of rubbing and the damage of blade and case caused by rubbing.