传递函数法轴承-转子系统不平衡响应抑制

Transfer Function Method for Suppressing of Unbalance Response of Rotor-Bearing System

为了解决残余不平衡力随着转子同步高速旋转时导致轴承-转子系统产生不平衡响应的问题,提出适当增大偏心率以提高油膜刚度、进而抑制不平衡响应的方法。基于动静压柔性铰链可倾瓦轴承,首先结合流量平衡原理与液体润滑雷诺方程得出轴瓦油膜的压力分布模型,并建立转子运动方程以及瓦块力矩平衡方程;然后提出轴承-转子系统的简化方法,并根据得到的简化系统的运动微分方程推导系统的标准传递函数;最后为确定人为增大偏心率的实施方案,研究了轴心定位策略,并通过最小二乘拟合法得到轴心位置-控制力方程。数值仿真结果表明:轴心定位策略能实现较高的定位精度,不平衡响应的抑制效果显著,x和y方向的振动幅值均降低为原来的10%左右。适当增大偏心率使得油膜刚度提高,能够有效抑制轴承-转子系统的不平衡响应。

In order to suppress unbalance response of rotor-bearing system caused by synchronous revolution of residual unbalance,a method,which is based on a hybrid flexure pivot-tilting pads bearing and considering increase the eccentricity to increase the oil film stiffness so that suppress unbalance response,is proposed.First,the oil film pressure distribution model is obtained by combining flow balance principle with Reynolds equation,and the torque equilibrium equation of pads and rotor movement function are built.Then,the standard transfer function of the simplified rotor-bearing system is deduced according to its differential equation of motion.Finally,the positioning strategy of desired position of rotor center is studied in order to determine the eccentricity control scheme,and the position-control force equation is fitted by the method of least squares.Results show that the proposed positioning method can achieve high positioning accuracy.Oil film stiffness can be improved by increasing the eccentricity and the unbalance response of the rotor-bearing system can be effectively restrained.The vibration amplitude of x and ydirection are both reduced to about 10% of the original.