偏心转子密封汽流激振机理分析

Mechanism of Steam Flow Excited Vibration with Eccentric Rotor

基于静偏心转子密封模型,对300 MW机组高压前五级隔板密封进行计算,得到偏心转子下密封流场的流动特性和压力分布,揭示偏心率与压力波动和汽流激振力的变化关系。结果表明:转子偏心导致密封内部压力在周向和轴向分布不均;随着偏心率增加,小间隙处的压力波动幅度增加,并出现压力高于大间隙的高压区;汽流激振力随偏心率呈非线性变化,非线性偏心率每增大20%,轴向推力增加1.1%~3.62%,径向力增加48.62%~326.77%,切向力的绝对值增加130.97%~242.9%。

Considering the effect of steam excited vibration on 300 MW steam turbine rotor,the flow characteristics and pressure distribution of the seal flow field under the eccentric rotor are calculated via static eccentricity model.The relationship between eccentricity,pressure fluctuation and nonlinear steam flow exciting force is revealed.The results show that the eccentricity of rotor leads to the uneven pressure distribution along circumferential and axial directions.The pressure fluctuation increases with eccentricity,a nd the pressure at small clearance is higher than that at large clearance.The exciting force varies nonlinearly with eccentricity.When eccentricity is increased by 20%,the axial thrust is increased by 1.1%~3.62%,radial force is increased by 48.62%~326.77%and absolute tangential force is increased by 130.97%~242.9%.