具有阻尼拉金和叶顶间隙的汽轮机末级复杂三维流动特性  

Study on Three Dimensional Flow of Last Stage With Lashing Wire and Tip Clearance in Steam Turbine

作　　者：李平[1] 张荻[1] 何林[1] 谢永慧[1] 

机构地区：[1]西安交通大学能源与动力工程学院,陕西省西安市710049

出　　处：《中国电机工程学报》2011年第8期80-86,共7页Proceedings of the CSEE

基　　金：国家高技术研究发展计划项目(863计划)(2009AA04Z102);教育部新世纪优秀人才支持计划(NCET-07-0682)~~

摘　　要：为获得具有阻尼拉金和叶顶间隙的叶栅通道内复杂流动的详细状况,采用重整化群湍流模型(RNG k-ε)、壁面函数法、结构化网格,混合平面法建立了三维黏性流动数值模型,基于该模型分析了某汽轮机末级的流动状况。结果表明:阻尼拉金附近沿叶片展向动叶表面静压、通道内流线分布均发生了显著变化,其中吸力面受到的影响更为显著。在叶顶和动叶吸力面上都发生了流动分离现象,表明该处存在分离涡和泄漏涡;同时,由于叶顶间隙的存在,动叶接近叶顶处压力面静压降低,甚至出现低于吸力面的情况,此外考虑阻尼拉金以及考虑阻尼拉金和叶顶间隙的汽轮机末级等熵效率与无阻尼拉金相比分别降低了0.39%和1.23%,表明泄漏损失在以上两种损失中占主要部分。In order to obtain the detailed information of the three-dimensional viscous flow in the last stage with lashing wire and tip clearance, the numerical model and calculation method was developed by adopting the renormalization group turbulence model （RNG k-ε）, wall-function method, structure grid and mixing plane approach. Numerical results indicate that the spanwise static pressure of blade and the streamline near the lashing wire change significantly, especially on the suction surface. It is shown that there are vortices system on the blade tip and suction surface as flow separation appears. Meanwhile, the static pressure on pressure surface near the blade tip reduce as the existence of tip clearance, and it was lower than the static pressure of suction surface in some region. Furthermore, for the isentropic efficiency of last stage, the model with lashing wire, the another model with lashing wire and tip clearance compared with the model without lashing wire and tip clearance show reduction of 0.36% and 1.14%, so the leakage loss is larger than that created by lashing wire. The numerical results obtained in this paper has the engineering application value and it can be used to improve the aerodynamic performance and reliability of turbine stage.

关 键 词：汽轮机 末级 阻尼拉金 叶顶间隙 数值模拟 

分 类 号：TK262[动力工程及工程热物理—动力机械及工程]