摘要
为了揭示叶顶间隙泄漏流动诱导汽流激振的规律,进一步提高汽轮机运行的安全性,本文采用数值模拟的方法,分析了汽轮机叶顶汽封腔室流场的细观特征,并将边界涡量流引入到叶顶汽封流场内,研究叶顶不均匀流场内的泄漏涡与汽流激振力之间的关联性。结果表明:当转子偏心运行时,汽封腔室涡的影响范围和旋涡强度不同,导致了围带面边界涡量流分布的变化,进而引起了围带面切向力的变化并诱导叶顶横向汽流激振力产生变化;而叶顶汽封间隙内的不均匀流场使围带面周向压力差发生变化,引起了叶顶径向汽流激振力的变化。当转子的偏心距相同时,叶顶汽封间隙流场的不同导致平齿汽封形式的叶顶横向汽流激振力最大,侧齿汽封形式的叶顶径向汽流激振力最大。动叶顶部装设平齿汽封更容易增加转子的不稳定性,而装设侧齿汽封对转子偏心涡动有一定的修正作用。
In order to reveal the law of the leakage flow of blade tip clearance inducing steamexcited vibration and further improve the safety of steam turbine operation, the numerical modeling method was used to analyze the mesoscopic characteristics of the flow field in the tip seal cavity, and the boundary vorticity flux was introduced into the flow field of tip seal to explore the relationship between the leakage vortices inside the uneven flow field and the steam-excited vibration force. The results showed that when the rotor ran eccentrically, the influence range of the vorticity in the seal cavity differed from vorticity intensity, leading to the distribution changes of boundary vorticity flux on the shroud surface, which further altered the tangential force on the shroud surface and induced the alternation of horizontal steam-induced excitation force. While the uneven flow field in the tip clearance changed the circumferential pressure difference on the shroud surface, which changed the radial steam-induced excitation force. When the rotors shared the same eccentricity, the different flow fields of the tip clearance maximized the horizontal steam-induced excitation force in the form of a flat-teeth seal, as well as the radial steam-induced excitation force in the form of a side-teeth seal. Installing the flat-teeth seal at the rotor tip is easier to increase rotor instability while installing the side-teeth seal can correct the eccentricity of the rotor to a certain extent.
作者
李盼
曹丽华
司和勇
胡鹏飞
薛川
LI Pan;CAO Lihua;SI Heyong;HU Pengfei;XUE Chuan(School of Energy and Power Engineering,Northeast Electric Power University,Jilin 132012,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2022年第11期2914-2925,共12页
Journal of Engineering Thermophysics
基金
国家自然科学基金资助项目(No.52176003)
东北电力大学博士科研启动基金项目(No.BSJXM-2021219)。
关键词
汽轮机
叶顶汽封
边界涡量流
汽流激振力
数值模拟
steam turbine
blade tip seal
boundary vorticity flux
steam-excited vibration force
numerical simulation