中文摘要：

这份报纸的目的是在设计下面并且离开设计条件改进最后阶段汽轮机和一台 600MW 蒸气汽轮机的 exhaust 兜帽的空气动力学的表演。在操作期间，在汽轮机和 exhaust 兜帽之间的强壮的流动相互作用在兜帽在流动行为上强加影响并且导致汽轮机的不能令人满意的空气动力学的表演并且用尽兜帽。exhaust 兜帽因此有潜力以空气动力学的效率被改善。就在汽轮机和 exhaust 兜帽之间的流动相互作用而言，更弥漫的结束墙的侧面被优化。联合模型汽轮机和模型用尽兜帽计算和实验被执行验证优化的效果。模型实验证明设计修正导致了全面压力恢复系数的实质的增加。流动和空气动力学的表演照原尺寸最后一台阶段汽轮机并且照原尺寸用尽兜帽被模仿探索流动物理改变到更弥漫的几何学的修正。湿蒸气作为流动媒介被选择。在不同操作条件下面的实际流动地被分析。

英文摘要：

The purpose of this paper is to improve the aerodynamic performances of the last stage turbine and the exhaust hood of a 600MW steam turbine under design and off design conditions. During operation, strong flow interactions between the turbine and the exhaust hood impose influences on the flow behavior in the hood and lead to the unsatisfactory aerodynamic performance of the turbine and exhaust hood. So the exhaust hood has the potential to be improved in terms of aerodynamic efficiency. Considering the flow interactions between the turbine and the exhaust hood, the profiles of the diffuser end-wall were optimized. The coupled model turbine and model exhaust hood calculations and experiments were carried out to validate the effects of the optimization. Model experiments show that the design modifications resulted in a substantial increase in the overall pressure recovery coefficient. The flow and aerodynamic performances of the full-scale last stage turbine and full-scale exhaust hood were simulated to explore the flow physics alterations to the modification of diffuser geometry. The wet steam was selected as the flow medium. The actual flow fields trader different operation conditions were analyzed.