具有前置凸台防旋板的汽轮机交错齿迷宫密封动力学特性研究  

Study on Rotordynamic Characteristics of the Staggered-Tooth Labyrinth Seal Mounting Anti-Swirl Brake with Upstream Rotor-Step in Steam Turbines

作　　者：殷戈 黄彪[2] 黄新长 邵峰 张子涵 李志刚[3] YIN Ge;HUANG Biao;HUANG Xinchang;SHAO Feng;ZHANG Zihan;LI Zhigang(Nanjing Electric Power Experimental Research Co.,Ltd.,Nanjing 210000,China;Dongfang Turbine Co.,Ltd.,Deyang,Sichuan 618000,China;Institute of Turbomachinery,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]国能南京电力试验研究有限公司,南京210000 [2]东方电气集团东方汽轮机有限公司,四川德阳618000 [3]西安交通大学叶轮机械研究所,西安710049

出　　处：《西安交通大学学报》2024年第6期53-64,共12页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(52176042)

摘　　要：为提高汽轮机多级轴端迷宫密封动力学性能,针对汽轮机两级轴端交错齿迷宫密封,开展了具有前置凸台的新型防旋板结构方案设计和止旋抑振性能评估。首先,针对两级轴端交错齿迷宫密封,设计了一级和两级传统防旋板、一级和两级前置凸台新型防旋板等动密封防旋板结构方案,并建立了具有“虚拟旁路边界”的有、无防旋板多级交错齿迷宫密封动力学计算模型,实现了对多级动密封进口压力场和高预旋速度场的精准模拟;然后,采用基于多频椭圆轨迹涡动模型的动密封气流激振动力学特性(CFD)摄动数值预测方法,对比分析了无防旋板、传统防旋板和新型前置凸台防旋板作用下,两级交错齿迷宫密封泄漏特性和气流激振动力学特性;最后,通过分析不同防旋板结构方案下,两级交错齿迷宫密封腔室旋流发展、腔室速度场和动态压力分布、转子面气流激振力,阐明了防旋板的止旋抑振机制。结果表明:无防旋板的迷宫密封具有最低的泄漏量,一级传统防旋板或一级前置凸台防旋板的设置会使密封齿数减少,导致密封泄漏量增加约4.5%;相比于一级防旋板,具有两级防旋板的迷宫密封泄漏量增加约5.5%;相比于传统防旋板,前置凸台防旋板可减小交叉刚度、增大有效阻尼;相比于一级防旋板,两级防旋板可减小高涡动频率下的交叉刚度、增大直接阻尼,进而提高密封的有效阻尼;在传统防旋板的基础上设置前置凸台可提升防旋板的止旋性能,且两级防旋板可有效抑制密封下游区域的旋流发展,能显著提升迷宫密封动力学性能、抑制汽轮机轴系振动失稳。To improve the dynamic performance of multi-stage labyrinth seal on turbine shaft,the structure design and performance evaluation of anti-swirl and vibration suppression are proposed for a new type of anti-swirl brake with upstream rotor-step in two-stage labyrinth seal with staggered teeth.Firstly,four types of anti-swirl brakes for two-stage staggered-tooth labyrinth seal are designed in this paper.In addition,a dynamic calculation model of labyrinth seal with“virtual bypass boundary”is established to achieve accurate simulation in the pressure field and high swirl velocity field.Then,a transient computational fluid dynamic CFD-based perturbation method based on the multiple-frequency elliptical-orbit rotor whirling model is adopted to analyze the leakage characteristics and dynamic characteristic coefficients of labyrinth seal with various anti-swirl brakes.Finally,the performance of anti-swirl and vibration suppression is elucidated by analyzing swirl velocity development,velocity field and dynamic pressure distribution of labyrinth seal.The results show that the labyrinth seal without anti-swirl brake has the lowest leakage,and the addition of the one-stage traditional anti-swirl brake or the one-stage anti-swirl brake with upstream rotor-step will reduce the number of seal teeth,resulting in the increase of seal leakage(by about 4.5%).Compared with the one-stage anti-swirl brake,the two-stage anti-swirl brake can further increase the leakage by 5.5%.Compared with the traditional anti-swirl brake,the swirl brake with upstream rotor-step can decrease cross-coupled stiffness and increase the effective damping.Compared with the one-stage anti-swirl brake,the cross-coupled stiffness of two-stage anti-swirl brake can be further reduced and the direct damping can be increased,so the effective damping can be significantly increased.Installing the upstream rotor-step on the basis of the traditional anti-swirl brake can improve the anti-swirl performance and two-stage anti-swirl brake can effectively suppress the

关 键 词：迷宫密封 泄漏特性 动力学特性 防旋板 

分 类 号：TK262[动力工程及工程热物理—动力机械及工程]