船用高速电机滑动轴承-转子系统圆度误差及不对中引起的振动机理与定量分析研究

In the vessel integrated power system, high-speed generator connected with prime power directly (cancel the gear system) can significantly improve the speed, power density and degree of integration, which has become the important development tendency of generation module in the vessel integrated power system. However, the mechanical vibration in high-speed generator is complex. The demand for vibration noise reduction design in the high-speed generator is urgently. Roundness error and misalignment inevitably caused by manufacturing tolerances, shaft deformation and wear of hydrodynamic journal bearing system are the major vibration factors in marine high-speed generator. Although the absolute size of tolerances of a journal bearing system is very small, when compared with the film thickness it is large enough to generate remarkable effects on system operating performance by changing the bearing clearance comparably. The effects are related to the coupling of bush, oil film and flexible rotor, among which the vibration mechanism and the quantitative relationship are complex. Aiming at this problem, a theoretical solution to the vibration analysis based on distributed oil film force and non-linear rotor dynamics allowing for roundness error and misalignment of the marine high-speed hydrodynamic journal bearing system are investigated in detail. Theory analysis and calculation of distributed oil film force and frequency characteristics are introduced considering factors of roundness errors and misalignment. Moreover, the flexible rotor dynamics model and boundary conditions are studied. At last, the detailed simulation model and method of distributed oil film force and system vibration considering the roundness errors, misalignment and rotor unbalance are proposed. The vibration coupling mechanism and quantitative relationship among bush, oil film and flexible rotor are reveled, which can provide theoretical reference for marine high-speed generator vibration and noise reduction design.

由于不受中压直流舰船综合电力系统中电频率的限制，采用直联式高速发电机组（取消减速齿轮箱，将高速原动机与发电机直接耦合）可大幅提高转速、功率密度和集成化程度，已成为舰船综合电力系统发电模块的重要趋势。而高速发电机中存在机械振动噪声大的问题，其中高速电机滑动轴承-转子系统受加工及装配误差影响，转频及倍频振动线谱突出且振动机理复杂，对其减振降噪设计的需求迫切。由于加工及装配误差、受载变形与磨损，轴颈表面圆度误差以及轴颈相对轴瓦倾斜量已和滑动轴承的油膜厚度相当，势必改变滑动轴承间隙，进而对系统的高速运行性能产生显著影响。为此本项目对船用高速电机滑动轴承-转子系统圆度误差及不对中引起的振动机理与定量分析进行深入研究，建立精细模拟圆度误差、不对中、转子不平衡因素下的分布油膜力及系统振动模型，揭示轴瓦-油膜-转子振动的耦合机理与定量关系，为船用高速发电机减振降噪设计提供理论支撑。

由于不受中压直流舰船综合电力系统中电频率的限制，直联式高速发电机组（取消减速齿轮箱，将高速原动机与发电机直接耦合）可大幅提高转速、功率密度和集成化程度，已成为舰船综合电力系统发电模块的重要趋势。而高速发电机中存在机械振动噪声大的问题，其中高速电机滑动轴承-转子系统受加工及装配误差影响，转频及倍频振动线谱突出且振动机理复杂，对其减振降噪设计的需求迫切。由于加工及装配误差、受载变形与磨损，轴颈表面圆度误差以及轴颈相对轴瓦倾斜量已和滑动轴承的油膜厚度相当，势必改变滑动轴承间隙，进而对系统的高速运行性能产生显著影响。.本项目对船用高速电机滑动轴承-转子系统圆度误差及不对中引起的振动机理与定量分析进行深入研究，建立了精细模拟圆度误差、不对中、转子不平衡因素下的分布油膜力及系统振动模型，揭示轴瓦-油膜-转子振动的耦合机理与定量关系，提出了一套考虑圆度误差及不对中因素的高速轴承-柔性转子系统振动定量预测方法，通过求解油膜动态分布将系统圆度误差及不对中因素引入柔性转子动力学方程中，实现系统振动的数值模拟。为综合分析高速轴承-柔性转子振动特性，细化轴承-转子系统的合理尺寸加工精度及装配对中度要求提供了理论依据。搭建了高速滑动轴承-转子系统振动试验方法与装置，为模拟系统加工及装配误差下的转子动力学及轴承振动提供一套科学、可行的研究平台。