三维角区分离是高负荷压气机内一种固有的流动分离现象，其形成于叶片吸力面与端壁（轮毂或者机匣）的连接处，严重制约了压气机负荷的提升。为了提高对三维角区分离现象和相关控制方法的认知，本文针对某一高亚音压气机内叶栅内的角区分离现象，开展了三维角区分离的形成机理、非定常动态特性及相关控制方法的研究。本文采用RANS和DDES两种数值方法，精确预测了压气机叶栅内的角区分离流动现象，并基于经过验证的数值计算结果，分析了角区分离形成过程中相关的流动结构和非定常动态特性。RANS及DDES时均结果表明三维角区分离的形成过程中伴随着多种旋涡结构的变化，包括前缘马蹄涡、前缘角涡、回流角涡、诱导涡、吸力面角区分离涡、集中脱落涡和通道涡等，并指出了前缘马蹄涡压力面分支、回流角涡和诱导涡的相互剪切作用形成一个展向涡，预示着角区分离的开始，其卷吸端壁低能流体沿展向迁移，然后在主流的挤压下形成了一个倾斜的大尺度流向涡——吸力面角区分离涡。角区分离涡在角区分离区域占主导地位，产生了大面积的速度亏损区域，使得叶栅出口的损失大幅增加。DDES模拟的瞬态流场分析表明角区分离是一个具有很强非定常性的流动现象，其形成和发展过程伴随着旋涡结构的非周期性脱落、破碎，导致了分离区与主流区的交界区域出现速度双峰现象。前缘攻角脉动和角区分离区域速度脉动的频谱分析表明大尺度涡的脱落、破碎过程与前缘马蹄涡相关，进一步说明前缘马蹄涡与角区分离的形成存在关联。湍流特性分析表明分离区的湍流状态是高度各项异性的。最后，本文探讨了壁面冷却对角区分离的影响机制，对比了叶片冷却、端壁冷却及联合冷却三种方式的控制效果。结果表明三种冷却方式均对角区分离有正面的控制效果，减小叶栅出口的总压损失，提升静压升系数。叶片冷却推迟了转捩的发生，减小了叶片跨中区域的叶型损失，在跨中转捩区域形成了湍动能更大的峰值区域，限制了二次流的展向迁移。端壁冷却则促进了二次流展向迁移，使得叶栅出口总压损失沿叶高分布更均匀。三种冷却方式均能减小角区分离区域内的回流角涡，但是叶片冷却对吸力面大尺度分离回流影响不明显，而端壁冷却和联合冷却则明显减小吸力面分离回流区的尺寸。

Three dimensional corner separation is an inherent flow separation phenomenon in the high loaded compressor, formed at the junction of the blade suction surface and endwall(the hub or casing), which seriously restricts the increase of compressor load.In order to improve the understanding of three-dimensional corner separation and related control methods, the formation mechanism, unsteady dynamic characteristics and related control methods of three-dimensional corner separation in a high Mach compressor cascade are studied in this paper.In this paper, the delay detached-eddy simulation(DDES) method and RANS method is used to accurately predict the corner separation flow in the compressor cascade. Based on the verified simulation results, the flow structure and unsteady dynamic characteristics during the formation of corner separation are analyzed. The RANS results and time averaged results of DDES show that the formation of three-dimensional corner separation is accompanied by the evolution of various vortex structures, including leading-edge horseshoe vortex, leading-edge corner vortex, concentrated shedding vortex, passage vortex, corner vortex with back flow, induced vortex and suction-side corner separation vortex. It is pointed out the shear between pressure-side branch of horseshoe vortex, corner vortex with back flow and induced vortex forms a spanwise vortex. The formation of this vortex structure indicates the beginning of corner separation, transporting the low momentum fluid in the boundary layer of the end wall along the spanwise direction. Under the extrusion of the mainstream it develops into a large-scale streamwise vortex, suction-side corner separation vortex. The corner separation vortex is dominant in the corner separation region, resulting in a large area of velocity loss region, greatly increasing the loss at the cascade outlet. The analysis of transient flow field based on DDES shows that the corner separation is a highly unsteady flow phenomenon, and its development process is accompanied by the non periodic shedding and breaking of the vortex structure, which leads to the bimodal phenomenon of velocity at the boundary of the separation zone and the non separation zone. The frequency spectrum analysis of incidence fluctuation near the leading edge and velocity fluctuation in corner separation region shows that the shedding and breaking process of the large-scale vortex is related to the leading-edge horseshoe vortex,which further illustrates that the horseshoe vortex is related to the formation of the corner separation. The analysis of turbulent characteristics shows that the turbulent state in the separation zone is highly anisotropic.Finally, the influence mechanism of wall cooling on corner separation is discussed. The control effects of blade cooling, end endwall cooling and combined cooling are compared. The results show that the three cooling methods have a positive control effect for the corner separation, reducing the total pressure loss at the cascade outlet and increasing the static pressure rise coefficient. The blade cooling delays the transition, reducing the loss of blade profile in the midspan region, and forms a peak region with larger turbulent kinetic energy in the midspan transition region, which limits the spanwise migration of the secondary flow. The endwall cooling promotes the spanwise migration of the secondary flow, which makes the total pressure loss at the cascade outlet more evenly distributed along the spanwise. All three cooling methods can reduce the recirculation corner vortex in the corner separation region. But the blade cooling has no obvious effect on the large-scale recirculation near the suction surface, while the endwall cooling and combined cooling significantly reduce the size of the recirculation region near the suction surface.