航空发动机转子振动的“热模态”和减振设计

“Hot modes” of rotor vibrations and vibration reduction design for aero-engines

为适应航空发动机变转速变工况下转子动力学设计,提出了航空发动机转子"热模态"的概念.利用两种模型解释了"热模态"的含义,并建立了"热模态"下转子动力学设计的方法.利用支承弹性转子(弹支转子)的临界转速与支承刚性转子(刚支转子)的临界转速之比作为优化参数,对转子进行优化设计,既包含了刚度的作用,也计及了质量的影响.结果表明:若所有"热模态"均在刚支转子的第1阶模态之下,则转子临界转速应尽量小于刚支转子的第1阶临界转速.若第1阶"热模态"在刚支转子第1阶模态之下,而第2阶"热模态"在刚支转子第1阶模态之上,但在刚支转子第2阶模态之下,则转子第2阶临界转速应取刚支转子第2阶临界转速和刚支转子第1阶临界转速之方均根值.除此之外,转子剩余不平衡量的分布应与刚支转子的模态正交.

A concept of ＂hot modes＂ of aero-engines rotor was put forward to adapt to the design of rotor dynamics for variable speed operation of aero-engines. The ＂hot modes＂ were explained with two different models, and a procedure of rotor dynamics design under ＂hot modes＂ was developed. The ratios of critical speeds of rotor with elastic supports to those of the rotor with rigid supports were taken as design parameters for dynamic optimiza- tion of the rotor, which involved the influences of stiffness, mass of the rotor. Result shows that, when all ＂hot modes＂ are under the first mode of rotor with rigid supports, the critical speeds of the rotor should be lower than the first critical speed of the rotor with rigid sup- ports. If the first ＂hot modes＂ under the first mode of rotor with rigid supports, and the sec-ond ＂hot modes＂ is between the first and the second modes of rotor with rigid supports, the second critical speed should be equal to the root mean square of the first and the second criti- cal speeds of the rotor with rigid supports. Additionally, it is suggested that the residual im- balance should be kept orthogonal to the modes of the rotor with rigid supports.