不同换算转速对高负荷风扇静子角区流动的影响

Effects on High-Load Fan’s Flow Structure in Stator Corner under Different Corrected Rotation Speeds

关键词:  高负荷风扇  角区流动分离  壁角涡  换算转速

Key words:  High-load compressor  Corner flow separation  Corner vortex  Corrected rotation speed

摘要:

为了探究影响高负荷风扇的失稳机制，对风扇第二级静子叶根角区气流分离的形成原因进行了研究，分析了不同换算转速对角区的流动状态以及壁角涡形成与发展的影响。研究表明，经过静子叶根前缘的气流逐渐发展形成了壁角涡，而壁角涡的存在促使了静子吸力面角区的气流分离，且随着风扇工况向近失速点移动，更多的角区气流直接参与了壁角涡的形成。在所研究的范围内，换算转速增加会导致壁角涡强度增加、影响范围扩大；在95% ~ 105%换算转速，壁角涡是引起角区气流分离的主要因素，而在85%换算转速，壁角涡已不再是引起角区气流分离和风扇失稳的主要原因。

Abstract:

In order to explore the instability mechanism of a high-load fan， the formation of the corner flow separation of the second stator in the two-stage fan was studied. The flow structure in corner and the development of corner vortex at different corrected rotation speed were analyzed. The results show that corner vortex is formed by the flow which pass the leading edge of stator root， and the corner vortex promote the corner flow separation of the second stator. While the fan condition is near stall， more flow in corner is involved in the formation of corner vortex. In the limits of the study， the increase of corrected rotation speed lead to the stronger corner vortex and its wider influence area. Corner vortex is the main reason of the corner flow separation at 95% ~ 105% corrected rotation speed， while corner vortex is not the major reason of the corner flow separation and fan instability at 85% corrected rotation speed.