新型柔性自适应迷宫密封泄漏特性研究

Investigation on Leakage Characteristics of Novel Flexible Self-adaptive Labyrinth Seal

迷宫密封是涡轮机械最常见的密封型式之一,对迷宫密封进行结构优化可降低机组工质泄漏率,提高运行效率。该文提出一种新型柔性自适应迷宫密封,通过在末级密封齿布置柔性齿结构,利用流场内形成的自然压差可自适应调整柔性齿形变程度,调整密封间隙。基于计算流体力学(computational fluid dynamics,CFD)方法与有限元法(finite element method,FEM)对柔性自适应迷宫密封进行流固耦合(fluid-structure interaction,FSI)分析,计算不同运行工况及柔性齿几何形状下柔性自适应迷宫密封形变及流场特性,得出泄漏特性变化规律,并与传统迷宫密封进行对比。结果表明:柔性自适应迷宫密封在工况变化时能维持低泄漏水平,在高压比下泄漏减少约26%,具有更好的封严性能,尤其可通过增大柔性齿长度、减小厚度,以增强流束收缩效应,提高新型密封泄漏控制效果。

Labyrinth seal is one of the most common sealing types in turbomachinery.Structural optimization of labyrinth seals can reduce fluid leakage rate and improve operational efficiency.In this paper,a novel flexible selfadaptive labyrinth seal is proposed.By incorporating flexible tooth structure in the end-stage sealing tooth,the deformation degree of the flexible tooth can be adaptively adjusted using the natural pressure difference formed in the flow field,thereby adjusting the sealing clearance.Fluid-structure interaction(FSI)analysis of flexible self-adaptive labyrinth seal based on computational fluid dynamics(CFD)and finite element method(FEM)is conducted.Deformation and flow characteristics of the seal under different operating conditions and various flexible tooth geometries are calculated to obtain the leakage characteristics,and then compared with the traditional labyrinth seal.The results demonstrate that the flexible self-adaptive labyrinth seal maintains low leakage level during changing operating conditions,reducing leakage rate by approximately 26%under high pressure ratios.Especially by increasing the length of flexible tooth and reducing its thickness,the flow contraction effect can be enhanced to improve the leakage control effect of the novel seal.