基于弯曲叶片的燃气涡轮导叶数值研究

Numerical Investigation for Curved Guide Vane in Gas Turbine

关键词:  燃气涡轮  弯曲叶片  二次流  气动性能  数值研究

Key words:  Gas turbine  Curved blade  Secondary flow  Aerodynamic performance  Numerical investigation

摘要:

采用三维数值方法，对小展弦比、考虑冷却的燃气涡轮弯曲导叶进行了三维流场模拟，通过对比分析不同的叶片弯曲方案，以探讨叶片弯曲控制二次流动、减小损失的机理。结果表明，由于导叶的径向二次流影响范围较小，正弯设计对叶栅气动性能的改善效果优于反弯；正弯设计能有效降低上端区的损失，最大降幅接近5%，而正弯和反弯设计都对下端区流动和损失影响较小。采用正弯设计后叶片吸力面的冷却效果变化不大，但显著降低了压力面的冷却效果，使得高温区域增加。

Abstract:

A low aspect ratio and curved turbine guide vane with cooling was investigated by 3-D numerical simulation. Through a comparative analysis of schemes with various bowing laws，the mechanism of controlling secondary flow and reducing losses was explored and discussed. The results show that as a result of a smaller range of radial secondary flow，a positively curved blade can improve aerodynamic performance of the cascade，which has a more effect than that of a negatively curved blade. A blade making use of positive curved design could effectively reduce the loss of the upper end-wall and the maximum amplitude of the loss reduction among different schemes reaches 5%. Positive and negative curved designs have little impact on the flow and loss of the lower endwall. When the positive curved design is put into use，the cooling effect of suction surface of the blade does not change a lot. However，the positive design significantly lowers the cooling performance of pressure side and this leads to a rise of high-temperature area.