汽轮机低压末三级耦合排汽缸的气动性能研究  

Numerical Investigation on Aerodynamic Performance of Last Three Stages and Exhaust Hood for Steam Turbines

作　　者：邵卫东[1] 杨建道[1,2] 杨锐 史立群 李军[1] 

机构地区：[1]西安交通大学叶轮机械研究所,西安710049 [2]上海汽轮机厂有限公司特殊透平与通流叶片研究所,上海200240

出　　处：《热力透平》2013年第3期150-155,共6页Thermal Turbine

摘　　要：为满足大型核电汽轮机低压排汽系统的开发,采用ANSYS-CFX软件数值求解Reynolds-Averaged Navier-Stokes(RANS)方程和k-ε紊流模型方法研究了低压缸末三级与排汽缸的变工况气动性能。结果表明:变工况显著改变了末级动叶的气动性能,对次次末级、次末级和末级静叶的气动性能几乎没有影响;排汽缸的气动性能受变工况的影响较大,小流量工况下的涡系结构发生较大变化,降低了扩压器静压恢复能力,增加了总压损失和改变了蜗壳内的流场;排汽缸背压减小导致透平级流量的降低和末级动叶出口气流角的变化,进而改变了排汽缸进口的流场特征。研究结果可以为汽轮机排汽缸的设计和优化提供理论支持。Aerodynamic performance of the last three stages and exhaust hood was numerically investigated to satisfy the development of exhaust system in large nuclear power steam turbines by using three- dimensional Reynolds- Averaged Navier- Stokes（RANS） and k - ε turbulent model based on the CFD software ANSYS- CFX. The detailed flow pattern of the exhaust hood and aerodynamic parameters of the last three stages was analyzed at two different flow conditions including the 75% designed operations. The numerical results show that the variable flow conditions markedly change the aerodynamic performance of last stage rotor and have little influence on the third last stage, second last stage and last stage stator. The vortex structure has a significant change at 75% designed working condition by comparison of the designed case, which decreases the static pressure recovery ability, increases the total pressure loss and changes the flow field in the volute. The decrease of back pressure results in the reduction of flow rate and yaw angle variation of last stage rotor. Moreover, the flow field characteristics of exhaust hood inlet change correspondingly. Relevant results of this study are expected to support the design and optimization of exhaust hoods.

关 键 词：汽轮机 排汽缸 低压透平级 气动性能 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]