200MW汽轮机低压转子-轴承系统的非线性动力学分析

采用数值计算方法对实际大型转子-轴承系统的非线性动力学特性进行了研究，计算结果能与现场的运行经验很好地吻合。用有限元法建立了200Mw汽轮机低压转子-轴承系统的非线性振动微分方程。采用Newmark逐步积分法对转子在升、降速过程中的振动响应进行了数值仿真，得到了转子发生油膜失稳的转速和油膜振荡的“惯性迟滞”现象。对转子的重力和不平衡量对系统的油膜涡动和油膜振荡的影响进行了计算和分析。计算得到了转子的振动随转子的偏心距、轴承的长径比、间隙比、润滑油粘度的变化规律，分析结果为定量和定性分析该类机组转子-轴承系统的稳定性提供了参考依据。图15表1参7

Nonlinear Vibration Analysis of a Low-Pressure Rotor-Bearing System for 200MW Steam Turbine

The nonlinear dynamical characteristics of a actual large-scale rotor-bearing system is firstly investigated by using numerical simulating method, and the computational results accord with the operating experiences. The nonlinear differential equation that govern the motion of a low-pressure rotor-beariong of 200MW turbine unit is presented using the FEM, and the Newmark method is applied to simulate the vibration responses of the rotor in the processes of increasing and decreasing rotational speed. It is obtained the instability threshold speeds of the system and the phenomenon "inertial sluggish" of the oil whip. The effect of the eccentricity and gravity of rotor on the oil whirl and oil whip is analyzed. The numerical results reveal the changing rule of the amplitude with the eccentricity of rotor, the clearance-to-radius ratio, the length-to-diameter ratio and oil viscosity of bearing. Figs 15, table 1 and refs 7.