风扇叶片丢失激励下转子-支承系统结构安全性设计策略

Structure safety design strategy of rotor-support system due to fan blade loss

以高涵道比涡扇发动机风扇叶片丢失载荷激励下的转子-支承系统为研究对象,提出了一套结构安全性设计策略,即通过支承方案与载荷分配、变刚度支承结构和支承结构变形控制,结合转子结构动力学特性设计,实现转子结构安全性设计.研究表明:风扇后支点采用变刚度支承结构设计,能够在转子减速停车过程中减小风扇局部振动临界转速与相应振幅.通过设计滚珠轴承支承锥壳锥角,能够使支承具有较高的轴向承载能力并减小转轴变形对滚珠轴承的影响.轴承座底部与转轴间采用鼓形配合面连接设计,能够在大弯矩作用下通过配合面相互滑移避免支承随转轴变形,保证轴承安全.研究结果可为恶劣载荷作用下高涵道比涡扇发动机结构安全性设计提供依据.

Taking the high bypass ratio turbofan engines as the research object for the rotor-support system under the load of blade loss, the strategies of structural safety design were put forward for the supporting scheme with loading distribution, variable stiffness sup- port structure and the deformation control of support structure. Combined with the dynamic design on rotor, the safety design was realized. Research showed that, the variable stiffness support design at the rear bearing could reduce the critical speed and corresponding vibration amplitude, leading to local vibration of the fan during the process of slowing down. Through the design on cone angle of the conical shell at the ball bearing, decreasing the influence of shaft deformation on the ball bearing and the support could withstand the big axial direction load. The design of drum-like matching interface between the bottom of bearing case and ro- tating shaft could avoid the support deformation through the matching surfaces slipping upon each other, thus ensuring the safety of the bearing. The research results can provide a technical reference for safety design on high bypass ratio turbofan engines under severe loadings.