变攻角下被动射流旋涡对高速扩压叶栅性能的影响

对被动射流旋涡(PJV)控制高速扩压叶栅内的流动分离控制展开数值研究,并探究其在变工况条件下的适应特性。结果表明,PJV在设计攻角下可使叶栅总压损失系数降低5.2%,变攻角条件下的损失降低幅度最高可达7.8%,表明其具有较高的控制效率和良好的变工况适应特性。随着攻角的增大,吸力面分离位置提前,射流出口与分离区间的距离减小,PJV能够更为有效地促进附面层内低能流体与主流间的动量交换,使得壁面涡结构得到重新组织,并进一步影响通道涡、集中脱落涡等涡系结构的发展,从而推迟流动分离、减小损失。在综合考虑变攻角流场特性的前提下,应使PJV的作用位置位于分离区上游不远处,所研究的最佳射流位置位于叶片前缘上游40%轴向弦长处。 

Effect of passive jet vortex on high-speed compressor cascade under different angles of attack

The application of passive jet vortex (PJV) on a high-speed compressor cascade for flow separation control was studied numerically. The effectiveness of the technique at off-design conditions was investigated. Results indicated that the PJV could reduce the total pressure loss coefficient by 5.2% at the designed angle of attack, and by 7.8% under different angles of attack, validating its high control efficiency and good adaptability. With the increase of the angle of attack, the flow separation on the blade suction surface would take place earlier and the distance between the jet exit and the separation region would decrease, which could strengthen the effect of PJV in enhancing momentum exchange and reorganizing the vortex structures like the passage vortex and the concentrated shed vortex within the passage, thus delaying the flow separation and reducing flow losses. Taking different angles of attack into consideration, it is suggested that the PJV be located near the upstream separation region. The optimum location of the jet is at 40% axial chord length from the blade leading edge.