结合面误差对盘式拉杆转子轴承系统动力特性的影响机理

The disk-bolt rotor is a sort of complicated combined rotor, in which many separated parts such as rotating disks are fastened together by several circumferential bolts or one central bolt. This kind of rotor structure has wide applications in heavy-duty gas turbines and aeroplane engines. Aimed at the features that joint surfaces have wide existence and errors on the surfaces are strictly restricted, 3D machining and assembly error models are built in the joint surfaces in the disks of complicated rotor. Combined with the assembly process, the influence of errors on the distribution status of combined rotor is investigated. The calculation and measuring method for obtaining the dynamic factors of joint surfaces and bolts with uneven forces are also studied. The coupling mechanism of stress distribution and dynamic factors is obtained for the disk-bolt rotor. The analysis method is developed for dealing with the 3D coupling features of stress and dynamic properties in the disk-bolt rotor bearing system with considering the effects of errors. The mechanism how the machining and assembly errors of joint surfaces influence the disk-bolt rotor system is revealed. Finally, the method for evaluating the errors in disk-bolt rotor is proposed, and the corresponding experiments are carried out for proving the numerical data. This research provides important reference for the machining precision design of the joint surfaces in the complicated combined rotors. Generally, this project can promote the domestic level for analyzing and designing the complicated rotor bearing system.

盘式拉杆转子是由若干周向拉杆或一根中心拉杆，通过预紧力将转子各部件结合为一体的复杂组合转子，这类转子在燃气轮机和飞机发动机等大型装备中具有广泛应用。针对盘式拉杆转子的结合面分布广泛和误差控制严格等特点，在轮盘部件结合面上建立典型加工及装配误差的三维模型，依照组合转子的装配流程，分析结合面误差对组合转子应力分布的影响，研究非均匀受力条件下结合面和拉杆的动力参数计算和测量方法，掌握盘式拉杆转子应力分布和关键动力学参数的耦合规律，发展含误差盘式拉杆转子的三维非线性应力动力联合分析方法，揭示结合面误差对此类组合转子轴承系统动力学特性的影响机理，并加以试验验证，以期给出结合面的误差评价方法和精度设计准则，对我国掌握此类复杂组合转子设计的核心技术起到积极作用。

本项目针对燃气轮机、航空发动机等盘式拉杆转子的结构特点，在轮盘部件结合面上建立典型加工及装配误差，依照组合转子的装配流程，分析结合面误差对组合转子应力分布的影响，分析发现缺陷带来不平衡，预紧造成转子初弯，离心力使得转子进一步弯曲；研究非均匀受力条件下结合面和拉杆的动力参数计算和测量方法，得到盘式拉杆转子应力分布和关键动力学参数的耦合规律，结果显示转子不平衡及弯曲量与误差基本成线性关系；建立含误差盘式拉杆转子的三维非线性应力动力联合分析方法，得到含误差盘式拉杆转子的稳定性域及振动特性，发现含误差盘式拉杆转子的稳定性比相应的整体转子小得多，并且振动幅值在过临界之后再次升高，从而解释了燃气轮机加工精度及动平衡难度比汽轮机转子高得多的原因；对比研究了形状度、同轴度、位置度等典型加工误差，发现这些误差对拉杆组合转子所造成应力及动力特性的影响规律基本一致，但形状度误差影响更为显著，由此提出了相应的加工误差设计方法；搭建了含误差盘式拉杆转子试验台，试验结果显示加工误差较大的转子振动幅值较大。本项目的相关研究说明，在进行盘式拉杆转子的动力设计时，仅仅避开临界的转子动力学设计准则是不足够的，还需要将拉杆预紧产生初弯的控制准则考虑进来，这进一步说明了三维转子应力、动力联合分析设计方法的必要性。