低アスペクト比蒸気タービン翼列の2次流れに関する研究(第2報)流れの制御技術

In order to develop the performance improving technology for low aspect ratio cascade of the steam turbine, the mechanism of secondary loss generation was investigated using smoke visualization and detailed internal flow measurement in phase 1. Next, in phase 2, flow control technologies such as the blade end fillet, endwall convergence and negative bow were introduced. This paper presents the loss reduction mechanism of these flow control technologies by applying computational fluid dynamics (CFD) and test results of the air model turbine to verify the effects of endwall convergence and negative bow in the rotating flow field. In conclusion, the technologies greatly contribute to improving the performance of the actual steam turbine with low aspect ratio cascade