射流式旋涡发生器对弯曲扩压叶栅流场的影响

Effects of vortex generator jet on the flow of bowed compressor cascades

数值模拟了射流式旋涡发生器对于大折转角弯曲扩压叶栅端壁流场性能的影响.结果表明:该研究的几种具有不同参数的射流式旋涡发生器都能使弯曲叶片损失降低,正弯和反弯叶片损失减小程度最大分别达2.5%和8.8%.射流除了可为端壁附近边界层中的低能流体提供动量之外,还可以在流道中产生与通道涡旋向相反、强度相当的流向旋涡挤压通道涡,使其向远离吸力面的方向偏转,该流向旋涡在距离叶片前缘0.6倍轴线弦长附近消失.对正弯叶片,吸力面上的流动分离现象基本消失,对于反弯叶片,极大程度上降低了吸力面集中脱落涡的强度.此外,射流作用使得弯曲叶片的负荷和折转能力均增加.

A numerical study of vortex generator jet application in bowed compressor cascades shows that, vortex generator jets with several kinds of parameters for both positive- ly and negatively bowed blade can reduce the total loss at most by 2.5% and 8.8% respec- tively. Moreover, the result reveals that the jet can not only apply momentum to boundary layer, but also create a streamwise vortex, which can deflect the passage vortex to make it rotate away from the suction side. The streamwise vortex is dissipated in the flow passage at 60 ~//0 axial chord length from the leading edge. For positively bowed blade, the flow separa- tion disappears on the suction side, and the concentrated shedding vortex is weakened for negatively bowed blade. Besides, the jet increases the blade loading and turning angle.