工业汽轮机排汽缸气动性能与流场结构的数值研究

Numerical study on aerodynamic performance and flow structure of industrial steam turbine exhaust hood

针对提高工业汽轮机排汽缸气动性能、改善流场、降低流动损失问题,采用数值仿真方法对一种铸造式工业汽轮机排汽缸进行了详细研究与分析。揭示了工业汽轮机排汽缸内部的流动机理与气动特性,提出了工业汽轮机排汽缸内的典型流场结构;提出了一种表征排汽缸气动性能的热力计算方法,并与西门子公司的实验修正数据曲线进行了对比分析;为逼近排汽缸真实状态下的入口条件,将工业汽轮机三级低压级叶栅与排汽缸进行了联合计算,同时对比分析了排汽缸中肋板等附加结构对气动性能的影响。研究结果表明:多元的旋涡运动是造成排汽缸流动损失的重要方面,排汽缸内部的附加结构会恶化流动,而合理的肋板布置会改善排汽缸出口流场。

Aiming at improving aerodynamic performance and the flow field,and reducing flow loss,a detailed research and analysis for a casting exhaust hood of an industrial steam turbine was carried out by numerical simulation. Flow mechanism and aerodynamic characteristics of the industrial steam turbine exhaust hood was revealed,and a typical flow field structure in the industrial turbine exhaust hood was proposed. A thermodynamic calculation method for characterizing the aerodynamic performance of the exhaust hood was presented,and analysis was carried out with the experimental data curve of SIEMENS. For more accuracy,calculation for the exhaust hood was coupled with three low-pressure stages and the effect of addition structure on aerodynamic performance was analyzed. The results indicate that the diversified vortex motion is an important aspect of flow loss,and the addition structure in the exhaust hood can deteriorate the flow structure,but reasonable steel plates can improve the exit flow field of the industrial steam turbine exhaust hood.