为解决透平机械多转子轴系动平衡需频繁多次启停机的问题,提出一种基于动力学响应分析的多转子轴系无试重虚拟动平衡方法.通过仿真构建与轴系结构尺寸和运行参数相符的有限元模型,分别在各转子平衡配重位置处施加虚拟不平衡激励,进行动力学稳态不平衡响应分析,得到轴系平衡转速下各振动测点处的振动响应值,从而避免需多次启机试重来获取轴系转子配重位置处的加重影响系数,结合实测的轴系不平衡振动基频值,通过矢量计算获得轴系各转子所需的平衡配重.采用搭建的四跨五支承透平机械轴系转子模拟试验台,应用该方法开展1 200 r/min低平衡转速下无试重虚拟动平衡试验,结果表明一次配重平均降幅高达55％,不仅减少了启停机次数,而且可降低因试重不当、测试误差所导致平衡失败概率;该方法还可推广应用到柔性转子轴系的现场动平衡.%In order to solve the problem of many times of starting up and shutdown in the dynamic balancing of turbomachine shaftings with multi-rotor,a virtual dynamic balancing method without trial weights for multi-rotor shaftings was developed based on dynamic response analysis.According to the shafting structure size and operation parameters,a rotor dynamic finite element model was built by virtue of the simulation technology.Unbalance excitations were applied on the nodes of the finite element model corresponding to the balancing weight positions of the multi-rotor of shaftings,and the vibration responses at each measuring point under the shafting balancing speed were obtained by the steady-state unbalance response analysis,which can replace the trial weight test with many times of starting up to get the weighting influential coefficients at specific balancing locations in the process of field whole-machine dynamic balancing.Then,combining with the initial fundamental frequency responses at shafting vibration measuring points,the required shafting balancing weights for each rotor were obtained through the vector calculation.A dynamic balancing experiment at the speed of 1 200 r/min without trial weights was taken by using the proposed method.The average amplitude reduction is up to 55 ％.The proposed dynamic balancing method can reduce the starting up and shutdown times and the probability of balancing failure due to improper trial weights and test errors.Moreover,it can also be applied to the field dynamic balancing of large flexible shaftings.
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