动静态汽封内部流场的数值模拟  

Numerical Simulation of the Flow Field in the Labyrinth Diaphragm Seal at Rotational and Static States

作　　者：曹丽华[1] 胡鹏飞[1] 徐伟[1] 李勇[1] 周云龙[1] 

机构地区：[1]东北电力大学

出　　处：《化工机械》2010年第5期617-621,共5页Chemical Engineering & Machinery

基　　金：吉林省科技发展计划项目(20080523);中国电机工程学会电力青年科技创新项目资助

摘　　要：将CFD软件作为计算平台,对汽轮机迷宫式隔板汽封内典型的三维紊流流场进行了数值模拟。应用结构化网格,采用有限体积法离散N-S方程和RNGk-ε双方程紊流模型封闭方程组。数值求解方法采用SIMPLE算法,迎风二阶格式求解对流项,迎风一阶格式求解扩散项。结果表明,转子的转动所带来的旋转效应对汽封内流体的轴向、径向、切向速度都产生影响,导致流体呈螺旋线流动,平均流速增大,湍动能耗散效应减弱,漏汽量比静止时有所增大。低压比时转速对漏汽量的影响较大,额定转速时的最大增幅达0.25%左右。A numerical simulation was carried out of the typical three-dimensional turbulent flow field in the labyrinth diaphragm seal of a steam turbine taking computational fluid dynamics（CFD）software as computing platform.The close equation set of the turbulent models of N-S equation and RNG k-εdouble equations was dispersed using structured network and finite volume method.SIMPLE algorithm was used for numerical solution method,the convective term was solved for upwind second order,the diffusion term was solved for upwind first order.The result shows that the rotational effect derived from the rotor rotation had an influence on the axial,radial,and tangential velocities of the fluid in the labyrinth diaphragm seal,the fluid flowed spirally,the average flow velocity was increased,the energy consumption effect of the turbulence was reduced,the leakage was increased to some extent than it was at static state.The influence of the rotational velocity on the gas leakage was comparatively much at low pressure ratio,the most range was about 0.25% at rated speed.

关 键 词：汽轮机 隔板汽封 泄漏 数值模拟 

分 类 号：TK14[动力工程及工程热物理—热能工程]