基于压电驱动浮环轴承间隙可调的涡轮增压器转子瞬变振动主动控制

Active Control of Transient Vibration of Turbocharger Rotor Based on Piezoelectric Drive Floating Ring Bearing Adjustable Clearance

针对涡轮增压器转子系统运行过程中频繁启停机、工作转速区间跨度大、转速变化快等条件下振动难以控制的问题,基于人工自愈工程理念,研究全转速范围油膜间隙与转子系统振动响应特性,提出采用压电陶瓷调节浮环轴承外油膜间隙改变系统阻尼从而实现转子系统振动快速、准确的控制。以某型汽油机涡轮增压器转子系统为例,分析推导出轴承油膜阻尼系数与其间隙的三次方成反比特性。构建不同外油膜间隙下浮环轴承转子系统动力学有限元模型,进行时域和频域非线性瞬态响应分析,得到全转速下的通频振幅和振动瀑布图,找出低中高三个转速段下转子系统最小振动幅值所对应的最佳油膜间隙,从而构建出油膜间隙与振动响应的映射矩阵。设计基于压电驱动下轴承座的外油膜间隙调节装置,采用分转速段振动主动控制策略,搭建相应的振动控制模拟试验装置,验证该控制系统的轴承间隙调节时间小于10 ms,最大位移误差小于0.5μm,可满足实时振动控制的要求。该方法可为高速转子机械振动控制提供新的思路。

Aiming at the problem that the turbocharger rotor system needs to be frequently started and stopped during operation,the working speed range is large,and the speed changes quickly,the vibration is difficult to control.Based on the concept of artificial self-healing engineering,the oil film clearance and the rotor system in the full speed range are studied Vibration response characteristics,it is proposed to use piezoelectric ceramics to adjust the outer oil film gap of the floating ring bearing to change the system damping so as to realize the rapid and accurate control of the rotor system vibration.Taking a certain gasoline engine turbocharger rotor system as an example,the damping coefficient of the bearing oil film is inversely proportional to the cubic power of its clearance.Construct a dynamic finite element model of the floating ring bearing rotor system under different outer oil film gaps,perform time-domain and frequency-domain nonlinear transient response analysis,obtain the frequency amplitude and vibration waterfall chart at full speed,and find out the three speeds of low,medium and high The best oil film gap corresponding to the minimum vibration amplitude of the rotor system under the section,thereby constructing the mapping matrix of the oil film gap and the vibration response.The outer oil film gap adjustment device based on the piezoelectric drive bearing seat is designed,and the vibration active control strategy in different speed segments is adopted,and the corresponding vibration control simulation experimental device is built to verify that the bearing gap adjustment time of the control system is less than 10 ms,and the maximum displacement error is less than 0.5μm,which can meet the requirements of real-time vibration control.This method can provide new ideas for mechanical vibration control of high-speed rotors.