【摘要】 以某600MW汽轮机为研究对象,应用计算流体力学软件CFX对低压缸末级和排汽缸的耦合模型进行了数值模拟,分析了导流环的起始扩散角、直径以及轴向长度对排汽缸气动性能的影响。结果表明:随着导流环起始扩散角的增加,排汽缸的气动性能得到改善,但当增加到30°时,在扩压器内会产生流动分离,其最佳值为25°;导流环的直径和轴向长度过大或过小均不利于排汽缸的气动性能,其中直径最佳值为5000mm,轴向长度最佳值为900mm。选取3个变量最佳值作为导流环的优化方案,与优化前排汽缸的气动性能进行对比,排汽缸出口的静压恢复系数提高了7.2%,总压损失系数降低了8.4%,气动性能有了明显的改善。更多还原

【Abstract】 A combined numerical simulation was conducted to couple fluid flow between exhaust hood and last-stage blades of a 600 MW steam turbine using the computational fluid dynamics software CFX. The influence of the initial diffusion angle,the diameter and the axial length of the guide on the aerodynamic performance of the exhaust hood was studied. The results indicate that the aerodynamic performance of the exhaust hood has been improved with the increase of the initial diffusion angle. There is a flow separation in diffuser when the initial angle increases to 30°. The most appropriate value is25°. It is not conducive to the aerodynamic performance of the exhaust hood that the diameter and the axial length of the guide are too large or too small. The most appropriate value of the diameter and the axial length of the guide are 5000 mm and 900 mm,respectively. The most appropriate value of the three variables was selected as the modification scheme of the guide. Comparing with the aerodynamic performance of the exhaust hood before reformation,the static pressure recovery coefficient of the outlet of the exhaust hood increases by 7. 2%,as well as the total pressure loss coefficient of the outlet of the exhaust hood reduces by 8. 4%. The aerodynamic performance is improved obviously.更多还原