Abstract: In order to reduce secondary flow loss and flow loss in the end-wall of large meridional expansion turbines， and reduce the influence of shortening transition section on turbine， aerodynamic analysis is carried out on the design of the compact transition section with large meridional expansion of the low-pressure turbine transition section， and the radial length of the compact transition section is reduced by 30%， and the aerodynamic performance and flow field state of the original turbine transition section and the shortened compact transition section are analyzed. In addition， the orthogonal design is adopted for the static turbine blade， and the effects of the orthogonal design on the flow performance of the large-meridian expansion turbine compact transition section are preliminarily explored. The study found that the compact transition section increased aerodynamic loss， but the overall efficiency increased by 1.32% after the turbine stator blade was designed with the orthogonal design. The orthogonal design can also improve the pressure distribution on the blade surface. The low-pressure core area on the suction surface is reduced from two to one. The exit loss of the flow passage is reduced and the overall aerodynamic performance of the turbine is improved.

Key words: Low-pressure turbine;Transition section;Blade;Flow performance;Aerodynamic performance;Othogonal design

摘要： 为了降低大子午扩张涡轮端区二次流损失和流动损失，同时降低过渡段缩短对涡轮性能的影响，对具有大子午扩张低压涡轮过渡段的紧凑过渡段设计进行气动分析，设计的紧凑型过渡段径向长度减小了30%，分析涡轮带原始过渡段和缩短后的紧凑型过渡段的气动性能和流场状态。并对涡轮静叶采用正交化设计，初步探索正交化设计对大子午扩张涡轮紧凑过渡段的流动性能的影响。研究发现，紧凑型的过渡段增加了气动损失，但涡轮静叶采用正交化设计后，整体效率提高了1.32%；正交化设计也能够改善叶片表面的压力分布，吸力面低压核心区从两个减少到一个；流道出口损失降低，涡轮整体气动性能提高。

关键词: 低压涡轮;过渡段;叶片;流动性能;气动性能;正交化设计