采用非定常数值方法求解了3种抽汽流量、2种密封间隙下中压缸迷宫密封转子动力特性系数，并将迷宫密封转子动力特性系数代入汽轮机轴系动力学特性模型中，开展了轴系稳定性分析，研究了迷宫密封运行参数变化对汽轮机轴系振动特性的影响。结果表明:在升功率过程中交叉刚度（负值）急剧增大，转子受到的侧向气流力急剧增大。随着密封间隙减小，抽汽口附近动叶叶顶密封交叉刚度增大6~7倍，转子受到的侧向气流力急剧增大。与0%TMCR工况相比，30%TMCR工况高中压转子1#轴承在一阶临界转速下，X方向振动增加最大为12.68%；50%TMCR工况下，1#轴承X方向振动增加7.01%，2#轴承Y方向减小最多为8.45%；增加中压缸密封间隙可以有效减小高中压转子振动量。

The rotordynamic coefficients of labyrinth seals in intermediate pressure cylinder were solved at three extraction flow rates and two sealing clearances using the unsteady numerical method. These coefficients were then substituted into the dynamic model of the turbine shaft system to analyze the stability of the whole shaft system. The impacts of labyrinth seals operating parameters on the vibration characteristics of the whole turbine shaft system were investigated. The results showed that during power increase process, the cross-coupled stiffness (negative value) is increased sharply, leading to a significant increase in the lateral fluid force acting on the rotor.? As the sealing clearance decreases, the cross-coupled stiffness of the shroud seal near the extraction port is increased by 6 to 7 times, resulting in a sharp increase in the lateral fluid force acting on the rotor.? Compared to the 0%TMCR condition, the vibration in the X direction of the high-pressure and intermediate-pressure rotors" #1 bearing at the first critical speed is increased by up to 12.68% under the 30%TMCR condition. Under the 50%TMCR condition, the vibration in the X direction of #1bearing is increased by 7.01%, while the Y direction of 2# bearing is decreased by up to 8.45%. Increasing the sealing clearance of the intermediate-pressure cylinder can effectively reduce the vibrations of rotors in high-pressure and intermediate-pressure cylinders.

陕西省自然科学(2018JQ5027)