轴流式轮机轮缘密封流动分析（英文）  

Analysis of the Rim Seal Flow in an Axial Turbine

作　　者：Alexej Pogorelov Matthias Meinke Wolfgang Schr?der 

机构地区：[1]Institute of Aerodynamics, RWTH Aachen University

出　　处：《风机技术》2019年第4期1-13,I0008,共14页Chinese Journal of Turbomachinery

基　　金：Research funded by FVV e.V.AiF Grant No.19198N

摘　　要：本文使用大涡模拟分析了带有30个定子和62个转子叶片的一级轴流式轮机轮缘密封内流动。Navier-Stokes方程的求解采用了基于笛卡尔浸入式边界和levelset方法的有限体积法。固体壁面位置由levelset方法追踪,然后在壁面边界采用了可以解析尖锐边缘并且严格体积守恒的切割细胞方法。本文生成了2个自适应笛卡尔网格,第一个网格使用levelset方法跟踪嵌入的表面边界,第二个网格用于离散流体域进行数值求解守恒方程。这种数值方法可以在同一个参照系下精确模拟涡轮机械应用中多个壁面相对运动的流动现象。数值仿真中精确解析了在圆周360度方向上的所有定子和转子叶片。数值仿真结果分析侧重于定子和涡轮级的转子盘之间单唇边密封结构内部空腔内流动。本文首先进行了网格分辨率研究,然后比较了LES结果和实验数据,最后详细分析了转子定子盘腔流场。分析结果确定了径向速度的主导模态,而且此模态与转子频率及其谐波都不相关。研究也表明,主导模态对热气进入转子定子盘腔的影响很大。The flow in the rim seal of a one-stage axial turbine with 30 stator and 62 rotor blades is analysed by large-eddy simulation(LES). The Navier-Stokes equations, are solved by a parallelized finite-volume solver based on a Cartesian immersed boundary/level-set approach. The rigid surfaces are tracked by a level set method and a sharply resolving and strictly conservative cut-cell formulation is used for the wall boundaries. Two adaptive Cartesian meshes are used, the first to track the embedded surface boundaries with the level set and the second to discretize the fluid domain for the numerical solution of the conservation equations. The overall numerical method allows highly resolved simulations of turbomachinery applications with multiple surfaces moving relative to each other in a single frame of reference. All stator and rotor blades are resolved, i.e., the domain comprises 360° in the cirumferential direction. The analysis of the simulation results focuses on the flow inside the cavity between the stator and the rotor disks of the turbine stage with a single lip rim seal configuration. A mesh resolution study is conducted first, before the LES results are compared to experimental data. Finally, a detailed analysis of the flow field inside the rotor-stator wheel space is conducted. A dominant mode of the radial velocity component is identified, which is unrelated to the rotor frequency and its harmonics. It is shown that this mode has a major impact on the ingress of the hot gas into the rotor-stator wheel space,.

关 键 词：涡轮机械 轴流式 流动分析 浸入式 轮缘密封 轮机 网格分辨率 密封结构 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]