建立迷宫密封实验装置与数值分析模型，研究进口预旋对密封系统静力与动力稳定性的影响，并以密封腔为单元对密封段转子受力进行分解，分析各密封腔在不同预旋情况下切向气流力变化影响。研究表明：各密封腔压力高点沿泄漏方向发生偏移是引起各密封腔切向气流力幅值及方向变化的原因；进口预旋可导致原压力高点发生偏移，其偏移方向与进口预旋方向一致，且越靠近进口偏移量越大；首个密封腔与其余腔室压力高点位置存在差异，导致其切向气流力随进口预旋比的变化趋势与其他密封腔相反；转子涡动将引起切向气流力整体偏移，但不改变进口预旋对各密封腔切向气流力作用效果；对于具有较多齿数的迷宫密封，正预旋将降低系统稳定性，而对于具有较少齿数的迷宫密封，正预旋有可能增加系统稳定性。

The experimental device and numerical analysis model for the labyrinth seals are established.The effect of inlet preswirl on the static and dynamic stability of the seal system is studied.The flowinduced force acting on the rotor is decomposed with the seal cavity as the unit and the effect of each seal cavity on the tangential flowinduced force with different preswirl rates is analyzed.The results show that the deviation of the high pressure spots of each seal cavity along the leakage direction is the cause of the variation of amplitude and direction of the tangential flowinduced force in each seal cavity.The preswirl can cause the deviation of the original high pressure spots,whose direction of deviation is consistent with the preswirl,and the closer to the inlet,the greater the deviation is.The position difference between the first seal cavity and the other cavities leads to the different trends of tangential fluid force with the inlet preswirl.The whirl of rotor will cause the overall deviation of the tangential flowinduced force,but does not change the effect of the inlet preswirl on the tangential force inside each seal cavity.For labyrinth seals with more teeth,negative inlet preswirl will increase system stability,while for labyrinth seals with fewer teeth,positive inlet preswirl will increase system stability.

TK730.2

国家自然科学基金（51875361，51575105）；中国华能集团公司科学技术项目（HNKJ17-H34）