轴流压气机转子尖部三维复杂流动Ⅰ——实验和理论研究

在低速大尺寸压气机实验台上,利用体视图像粒子测速(SPIV)技术测量了设计状态和近失速状态转子尖部的三维复杂流动,对典型二次流流动结构的特性及其产生、发展和演化机制做了研究。实验测量覆盖整个转子通道,从测量得到的各阶物理量中可以识别出叶尖泄漏涡、角区旋涡、通道涡和进口导叶尾迹等多种二次流流动结构。通过分析各种二次流流动结构造成的流动堵塞和损失发现:在设计状态,叶尖泄漏涡是流动堵塞和损失的主要来源,在转子出口处造成的流动堵塞约为总流量的0.35%;在近失速状态,角区旋涡对流动堵塞和损失的分布起了决定性作用,造成的流动堵塞可以达到总流量的8.5%。最后,借鉴二次流理论对角区旋涡的产生、发展和演化机制做了理论分析,结果表明角区旋涡的发展过程主要由流向速度的展向分布规律决定。

Three-dimensional Flows near Rotor Tip in an Axial Compressor Ⅰ——Experimental and Theoretical Studies

The flow fields near the rotor tip region of an axial compressor are measured by stereoscopic particle image velocimetry (SPIV) on a large-scale low-speed axial compressor test facility under both the design and near-stall conditions, and the flow mechanisms of some typical secondary flow structures are studied. According to the measured results, many secondary flow structures can be identified, such as the tip leakage vortex, corner vortex, passage vortex and inlet guide vane wake. Among these complicated flows, the tip leakage vortex and corner vortex are the two key flow structures contributing to large flow blockages and losses. In the design condition, the evolution of tip leakage vortex determines the flow blockage and causes a blockage of about 0.35% of the total massflow at the outlet of the rotor passage. In the near-stall condition, the corner vortex causes the most significant flow blockage and makes a maximum blockage of about 8.5% of the total massflow inside the rotor passage. Finally, theoretical analysis is made to clarify the evolution mechanism of the corner vortex. The results show that the evolution of the corner vortex is mainly determined by the spanwise distribution of the streamwise velocity in the rotor passage.