防旋板与转子面一体化设计的迷宫密封转子动力特性研究

Rotordynamic Characteristics of Labyrinth Seals with Integrated Design of Swirl Brake and Shaft Configuration

为提高迷宫密封转子动力特性,开展进口和腔室防旋板与转子面一体化设计的迷宫密封结构转子动力特性研究。基于进口防旋板结构的迷宫密封(结构1),设计了进口和腔室防旋板结构的迷宫密封(结构2),以及基于结构2的带有腔室防旋板与转子面凹槽和凸台结构一体化设计的密封结构3和4。采用转子多频椭圆轨迹涡动模型和动网格技术的非定常Reynolds-averaged Navier-Stokes(RANS)数值求解方法,对比分析了变进口预旋条件下4种迷宫密封的泄漏特性和转子动力特性。研究表明:相比于进口防旋板密封,腔室防旋板和转子面一体化设计的凹槽和凸台转子面密封,特别是凸台转子面密封能明显降低迷宫密封的泄漏量和交叉刚度;进口预旋比为0.84时,相比于进口防旋板密封,凹槽转子面密封和凸台转子面密封的正有效阻尼分别提高了48.7%~144.1%和59.8%~254.0%;进口预旋比增加为1.32时,凹槽转子面密封和凸台转子面密封在整个频率范围内仍保持最大有效阻尼。腔室防旋板和转子面一体化设计的迷宫密封能显著提高转子稳定性,论文工作为进一步提高迷宫密封的转子动力特性提供了设计方案。

The rotordynamic characteristics of labyrinth seals with integrated design of swirl brake and shaft configuration were studied to further improve the rotordynamic performance of labyrinth seals.In this research,4 types of labyrinth seal structures were covered,namely,the labyrinth seal with inlet swirl brake(structure 1),the labyrinth seal with inlet and cavity swirl brakes(structure 2),the labyrinth seal designed based on structure 2 with integrated cavity swirl brake and rotor groove shaft(structure 3),and the labyrinth seal designed based on structure 2 with integrated cavity swirl brake and rotor convex shaft(structure 4).Their leakage and rotordynamic characteristics under different preswirl conditions were comparatively analyzed by using the unsteady Reynolds-averaged Navier-Stokes(RANS)numerical solution methods based on the multi-frequency elliptical orbit rotor whirling model and the dynamic mesh model.The obtained results show that compared with structure 1,the leakage flow rate and the cross-coupling stiffness of structures 3 and 4,especially structure 4,can be obviously reduced,the positive effective damping of structures 3 and 4 increases by 48.7%-144.1%and 59.8%-254.0%,respectively when the inlet preswirl ratio is 0.84,and structures 3 and 4 can maintain the maximum effective damping over the whole frequency range when the ratio increases to 1.32.It is thus concluded that labyrinth seals with integrated design can significantly enhance the rotor stability,and this work can provide a design basis to further improve the rotordynamic performance of labyrinth seals.