Abstract: In high endwall angle turbine，the large meridional expansion flow would cause a large secondary flow of endwall resulting in a larger end wall flow losses than normal turbines. In order to optimize the endwall flow and reduce the end wall flow losses in high endwall angle turbine cascade，the original blade has been replaced by the orthogonal blade in the first stage of a type of turbine. The numerical calculation has been taken with the original turbine and the turbine used orthogonal blades. The results indicated that，the efficiency of the turbine increased by using orthogonal blades as vanes. Orthogonal turbine makes the flow of the casing endwall and hub endwall leveling off. The passage vortex of the casing endwall is reduced. The flow of casing endwall move along the C type pressure field to the middle part of the blade，the flow losses of end wall are reduced. The flow loss at the middle of the blade and the hub endwall also decreased. But the radial static pressure gradient decreases obviously，the boundary layer radial string get improved，the efficiency of the first stage of turbine has improved 0.74%，the location of blade which have obtained most improvement is 80% to 90% of spanwise，and the power of the first stage turbine has improved 0.69%.

Key words: Turbine；High endwall angle；Orthogonal blade；Endwall losses；Aerodynamic performance

摘要： 在大子午扩张涡轮中，流道的子午扩张会造成较强的端部二次流动，从而产生较大的端区损失。为重组大子午扩张端区流动以减小端区损失，对燃气轮机动力涡轮第一级静叶进行正交设计优化，并对重新设计的正交叶片和原型叶片进行数值模拟计算及对比分析。研究结果表明，采用正交叶片作为大子午扩张静叶的涡轮级效率有明显提高，正交涡轮使得上下端壁的流动趋于平缓，并使得上端壁的通道涡减小，上端壁的流动沿“C”型压力场向叶片的中部移动，减少了端区的流动损失。在叶中和叶根部分流动损失也得到了减小。同时径向静压梯度明显减小，改善了附面层径向的串动，第一级涡轮的效率提升了0.74%，主要提升位置在80%到90%相对叶高处，功率提高了0.69%。

关键词: 涡轮；大子午扩张；正交叶片；端区损失；气动性能