压气机二维动叶栅非定常流场的大涡模拟

对压气机二维动叶栅,采用单通道和多通道计算模型进行了大涡模拟(LES),研究了节流过程中内部流场的非定常波动特征,分析了旋涡结构和波动频率的变化规律.结果表明:大流量工况时,前缘绕流和叶片吸力面分离产生的两种非定常波动共存,波动频率随压气机节流基本保持不变,此时吸力面分离表现为小尺度旋涡结构;近失速工况时,吸力面发生大尺度的流动分离,波动频率明显下降,低于叶片通过频率. 

Large eddy simulation of unsteady flow field in a two-dimensional moving compressor cascade

Using single-passage and multi-passage caculation models, large eddy simulations were conducted to study the unsteady oscillating features of internal flow field in a two-dimensional moving compressor cascade during the throttling process. The changes of vortex structure and oscillating frequency were analyzed. The resutls show that at working conditions with larger mass flow rates, two unsteady oscillations resulted from flow around leading edge and separation on blade suction surface coexist. Both frequencies almost keep constant. Flow structures of separation on suction surface are of small scale. At working conditions near stall limit, large scale separations occur on suction surface. The oscillating frequency decreases dramatically, lower than blade passing frequency.