汽轮机密封内流场计算及流激振力计算分析

论文总字数：28651字

摘 要

本文建立了迷宫密封内部流场及汽流激振力的分析模型，运用计算流体力学（CFD）技术对迷宫密封内部流场及汽流激振力的影响因素进行了简要分析，研究结果表明：对于密封泄漏量来说，转速、进口预旋对密封泄漏量基本不会造成影响，随着压比和偏心的增大，密封泄漏量会同步增加。随着密封齿数的增加，密封泄漏量会降低。对于气流激振力来说，随着压比、偏心、进口预旋的增大，转子上的汽流激振力都会随之增大，而密封齿数的增加也会导致转子激振力增加。综合上述结果，本文对如何减小密封泄漏量和抑制汽流激振力进行了简要分析，提出了几条优化建议。

关键词：汽轮机，迷宫密封，计算流体力学，泄漏量，切向力

The calculation and analysis of Flow Field and Flow Induced Force in Turbine Seal

03311515 marui

Supervised by yangjiangang

Abstract：Modern power technology has been basically formed, but thermal power generation technologies still in development, which makes people increasingly high demand for thermal power equipment manufacturing process, technical indicators, economic performance properties. The leakage of fluid and the vibration force of the steam flow are the important reasons for the turbine efficiency and safety operation.. So the turbine seal flow field and in the study of excitation force of steam flow, is of great significance to the stable, efficient operation of steam turbine.

In this paper, we establish the labyrinth seal and inner flow field of steam flow excitation force analysis model, using CFD technology of labyrinth seal and inner flow field of steam flow excitation force of influence factors are briefly analyzed. The research results show that: for seal leakage amount, rotational speed, inlet pre swirl of seal leakage will not impact, with the pressure ratio and the eccentricity increases, seal leakage will be increased at the same time. With the increase of the number of seal teeth, the leakage of seal is reduced.. For the air exciting vibration force, with pressure ratio, the increase of eccentricity, inlet pre swirl, the rotor of steam flow excitation force will increase, and the sealing tooth number increases will also lead to an increase in rotor exciting force. From the above results, the paper briefly analyzes how to reduce the leakage quantity and restrain the steam flow induced vibration, and put forward some optimization suggestions..

KEY WORDS：Turbine，labyrinth seal，computational fluid dynamics，tangential force，leakage

目 录

摘要 -----------------------------------------------------------------------Ⅰ

Abstract --------------------------------------------------------------------Ⅱ

目录 -----------------------------------------------------------------------Ⅲ

1 研究背景及意义 -----------------------------------------------------------01

1.1 绪论 -------------------------------------------------------------------01

1.2 密封技术研究现状及种类 -------------------------------------------------01

1.2.1 迷宫密封 -------------------------------------------------------------02

1.2.2 蜂窝密封 -------------------------------------------------------------02

1.2.3 刷式密封 -------------------------------------------------------------03

1.2.4 混合式密封 -----------------------------------------------------------03

1.3 迷宫密封简介 -----------------------------------------------------------04

1.3.1 迷宫密封分类 ---------------------------------------------------------04

1.3.2 迷宫密封机理 ---------------------------------------------------------04

1.3.3 迷宫密封的特点及应用 -------------------------------------------------05

1.4 迷宫密封内流场计算国内外研究现状 ---------------------------------------05

1.4.1 热力学分析方法 -------------------------------------------------------06

1.4.2 数值计算 -------------------------------------------------------------06

1.5 迷宫密封动力特性国内外研究现状 -----------------------------------------06

1.5.1 控制体模型 -----------------------------------------------------------06

1.5.2 计算流体力学模型 -----------------------------------------------------07

1.6 主要工作 ---------------------------------------------------------------07

2 迷宫密封泄漏特性研究 -----------------------------------------------------08

2.1 CFD数学模型 -----------------------------------------------------------08

2.1.1 控制方程 -------------------------------------------------------------08

2.1.2 湍流模型 -------------------------------------------------------------08

2.1.3 近壁面处理 -----------------------------------------------------------09

2.2 迷宫密封泄漏量计算公式 -------------------------------------------------09

2.3 计算模型 ---------------------------------------------------------------10

2.4 网格划分 ---------------------------------------------------------------11

2.5 边界条件设置 -----------------------------------------------------------12

2.6 模型计算结果 -----------------------------------------------------------12

2.7 迷宫密封泄漏特性影响因素分析 -------------------------------------------13

2.7.1 压比对泄漏特性的影响 -------------------------------------------------13

2.7.2 转速对泄漏特性的影响 -------------------------------------------------14

2.7.3 齿数对泄漏特性的影响 -------------------------------------------------14

2.7.4 偏心对泄漏特性的影响 -------------------------------------------------15

2.7.5 预旋对泄漏特性的影响 -------------------------------------------------16

2.8 减小密封泄漏的措施 -----------------------------------------------------16

3 迷宫密封动力特性研究 -----------------------------------------------------17

3.1 迷宫密封汽流激振形成机理 -----------------------------------------------17

3.1.1叶顶间隙不均匀产生的激振力 --------------------------------------------17

3.1.2密封间隙不均匀产生的激振力 --------------------------------------------17

3.1.3部分进汽和转子偏心等因素产生的静态汽流力 ------------------------------18

3.2 迷宫密封动力特性模型及稳定性分析 ---------------------------------------19

3.2.1 密封动力特性模型 -----------------------------------------------------19

3.2.2 密封动力特性对转子稳定性的影响 ---------------------------------------20

3.3 迷宫密封动力特性CFD求解方法 ------------------------------------------20

3.4 计算模型 ---------------------------------------------------------------20

3.5 网格划分 ---------------------------------------------------------------20

3.6 边界条件设置 -----------------------------------------------------------20

3.7 迷宫密封动力特性影响因素分析 -------------------------------------------21

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