摘要
为了准确预测水轮发电机组轴系统的自振特性,防止轴系统因振动而发生破坏,采用有限单元法对机组的临界转速进行了计算。鉴于水电机组为刚性轴,校核时需要保证轴系统的一阶弯曲临界转速大于飞逸转速的1.2倍,同时保证轴系统的扭转临界转速频率远离电气激发频率。由于发电机转子不位于两个导轴承的中点,同时水轮机转轮位于轴的外伸端,转子在弓状回旋时存在着陀螺效应,笔者分析了陀螺效应对轴系统弓状回旋自振特性的影响,得出了计算机组临界转速时不能忽略陀螺效应的结论。
To precisely predict the self oscillation of the shaft system of the turbine-generator unit and avoid failure occurrence of the shaft system because of oscillation, the finite element method is applied to calculate the critical rotating speed of the unit. As the unit is of the rigid shaft, its critical rotating speed of the first order bending of the shaft system higher than 1.2 times runaway rotating speed shall be guaranteed. Simultaneously, frequency of the torsional critical rotating speed of the shaft system shall be away from the electrical excitation frequency. As the rotator is not seated at the middle point of the two guide bearings as well as the runner is at the external extension of the shaft, the gyroscopic effect occurs while the arcuate convolution is available. Impacts of the gyroscopic effect on the self oscillation of the shaft system are analyzed. It concludes that the gyroscopic effect shall not be neglected while the critical rotating speed of the unit is calculated.
出处
《西北水电》
2017年第4期23-28,共6页
Northwest Hydropower
关键词
自振特性
临界转速
陀螺效应
弓状回旋
有限单元法
self-oscillation
critical rotating speed
gyroscopic effect
areuate convolution
arcuate convolution
finite element method