长周期变转速下入口油温对高速轻载涡轮增压器转子振动特性影响

Effect of Inlet Oil Temperature on Vibration Characteristics of High-speed Light-load Turbocharger Rotor under Long Period and Variable Speed

高速轻载涡轮增压器转子系统的入口油温在长周期变转速运行条件下会产生动态变化,从而改变转子系统振动特性甚至导致非线性振动事故。以某型汽油机用高速轻载涡轮增压器转子为研究对象,分析浮环轴承内油膜最小厚度与偏心率随入口油温参数的变化规律,构建涡轮增压器转子-浮环轴承系统动力学有限元模型,采用Newmark积分法分析转子系统的非线性瞬态响应,结合涡轮增压器升速实验,得到不同入口油温下转子系统三维振动瀑布图与Colormap频谱图,探究入口油温对转子系统振动响应特性的影响。结果表明:随着入口油温从50℃增至130℃时,内油膜最小厚度会减少,环速比与偏心率会增加,内油膜振荡幅值逐渐降低,但出现内油膜振荡与外油膜涡动的轴颈转速点会提前约30%,且外油膜涡动幅值会逐步增加。综合内外油膜涡动与振动幅值,入口油温约为90℃时转子振动情况较好。结论可为设计具有智能抗振性能的高速轻载涡轮增压器转子系统的运行参数提供理论参考。

The inlet oil temperature of high-speed and light-loaded turbocharger system changes dynamically under the operating conditions of long period and variables speed, thus changing the vibration characteristics of the rotor system and even leadi ng to nonlinear vibration accidents. High-speed and light-load turbocharger system for a certain type of gasoline engine is studied. The variation of minimum thickness and eccentricity ratios of inner oil film in floating ring bearing with different inlet oil te mperature is analyzed. The dynamic finite element model of turbocharger rotor-floating ring bearing system is constructed. Under the turbocharger speed up experiment and simulation calculation, adopting Newmark integral method to analyze the nonlinear transient response of the rotor system, the waterfall and Colormap of the rotor system are obtained under different inlet oil temperatures. Exploring the influence of inlet oil temperature on vibration response characteristics of rotor system. The results show that when inlet oil temperature rises from 50 ℃ to 130 ℃, the inner oil film minimum thickness decreases, the ring speed ratio and eccentricity ratios increase, and the whip amplitude of the inner oil film decreases gradually. But the rotational speed of the journal is earlier approximately by 30% when inner oil film whip and outer oil whirl, the outer oil film whirl amplitude is gradually increased. Considering the inner and outer oil film whirl and vibration amplitude, the rotor vibration reaches to the lowest level when the inlet oil temperature is about 90 ℃. Such findings can provide theoretical reference for future design of high speed and light-loaded turbocharger systems with intelligent anti-vibration performance feature.