低雷诺数下压气机的二次流旋涡结构

为了探究高空低雷诺数条件下跨声速压气机的流动规律,对NASA Rotor37进行单通道数值模拟,探索其在低雷诺数进气条件下二次流的旋涡结构.研究发现:马蹄涡压力面分支诱发压力面角区诱导涡,壁角涡形成了顺流和逆流的两段式结构,脱落涡由叶根角区发展起来后不断从尾缘脱落,泄漏涡近失速点仅局部破裂不是失稳触发的主要原因.通道中的激波系诱发了吸力面和压力面的两个径向涡,压力面径向涡构成闭合的气泡式分离,吸力面径向涡在叶顶的破碎诱导产生分离涡,触发了低雷诺数下压气机的失稳.流场旋涡结构由马蹄涡、壁角涡、径向涡、泄漏涡、分离涡、脱落涡6个大尺度旋涡以及其他小尺度旋涡组成.

Vortex structure of secondary flow in transonic axial compressor with low Reynolds number

To explore the flow pattern under conditions of high altitude low Reynolds number in transonic compressor, simulation for NASA Rotor37 was conducted to probe for its vortex structure in secondary flow at high altitude condition. The study finds that the pressure side branch of horseshoe vortex induces a small-scale vortex located on the pressure side corner area near hub, corner vortex form a two-stage vortex with downstream and upstream directions, shedding vortex is developed from blade root and shed from the trailing edge, and leakage vortex near stall point only partially rupture, not as the main reason for the instability. Channel shock waves induce two radial vortexes near suction side and pressure side, the pressure side radial vortex forms a closed bubble separation, suction side radial vortex crash in blade tip passage and induce separation vortex, triggering compressor's instability under low Reynolds number. Vortex structure is consisted of horseshoe vortex, corner vortex, radial vortex, leakage vortex, separation vortex, shedding vortex and other small-scale vortexes.