基于流迹显示技术的前弯跨声速压气机叶栅通道三维流动测量

The measurement of the three-dimensional flow on the forward-skewed transonic compressor blade based on the flow trajectory visualization technology

为了研究前弯跨声速压气机叶栅通道的三维流动状况,利用流迹显示技术,对不同攻角下的流动图谱进行了测量,并针对负攻角以及零攻角、正攻角工况提出了两种流动模型。研究表明,叶片表面层流的转捩形式与攻角无关,压力面均在前缘以旁路转捩形式完成转换,吸力面以层流分离泡形式完成分离转捩。在三维流动结构上,负攻角时流动较为简单,为前缘马蹄涡对、通道涡、吸力面尾缘处壁角涡构成的涡系结构;零攻角与正攻角时,还存在压力面前缘诱导角涡、压力面侧的通道诱导涡的涡系结构。此外,受吸力面尾缘集中脱落涡的影响,压力面尾缘出现了向前缘的回流,导致出现了鞍点三维分离特征线;且在压力面前缘诱导涡轴向流动的黏性与轴向逆压梯度作用下,压力面还出现了附着螺旋点与分离螺旋点的三维分离流动特征。

In order to study the three-dimensional flow of the forward-skewed transonic compressor cascade passage, the oil flow test was carried out at negative, zero and positive angle of attack. A pair of flow models was set under the condition that the blade surface was independent on the angle of attack,bypass transition was founded at the pressure surface leading edge, while separation transition occurred by laminar separation bubble. The flow structure was quite simple at negative angle of attack. The vortices were made of the pair of leading edge horse vortex, passage vortex, and suction surface corner vortex. Besides the pressure surface leading edge corner vortex, pressure surface corner was founded at the positive and zero angle of attack. Affected by the suction surface trailing edge shedding vortex, the backflow was founded at the area between the pressure surface trailing edge, and the saddle point threedimension separation characteristic line occurred. Otherwise, the reattachment spin spot and separation spin spot were induced at the pressure surface by the viscosity of the pressure surface leading edge induced vortex axial flow and the axial adverse pressure gradient.