压气机动静叶干扰的非定常流动特性

采用大涡模拟(large eddy simulation,LES)方法计算动叶尾迹对静叶干扰的流场信息。利用涡量分布揭示动叶尾迹在静叶通道内的演化过程,利用压力梯度识别激波结构及波振源,运用动力学模态分解(dynamic mode decomposition,DMD)方法对静叶通道内流场的时空结构进行模态分解。结果表明:流场中存在3处波振源,分别位于动叶尾缘、静叶前缘和静叶尾缘处；发现静叶通道内流场的频谱具有多峰值现象,模态分解的第1阶流动代表动叶尾迹在通道内随时间迁移,对应频率为动叶通过频率(blade passing frequency,BPF)是通道内旋涡非定常波动的主导频率；第2阶流动是动叶通过频率的2倍频流动,旋涡的空间尺度为1阶模态的1/2,为更小尺度的扰动。 

Unsteady flow characteristic of rotor-stator interaction in compressor

Flow of stationary blade interference with the rotor wake was simulated using the large eddy simulation (LES) method. The coefficient of vorticity was used to reveal the evolution mechanism of rotor wake in the stator passage, and the pressure coefficient gradient was used to discriminate the shock structure and wave source. The flow characteristics of the temporal and spatial structures in the flow field were analyzed by dynamic mode decomposition (DMD). Result showed that three wave sources were found at the trailing edge of the moving blade, the leading edge of the stationary blade and the trailing edge. Multi-peak of the frequency spectrum was found in a stator passage flow field. The first order mode represented the transport of wake in the passageway and corresponded to the flow of rotor blade passing frequency (BPF), its unsteady fluctuation was dominant in the flow field. The second order mode was twice of the rotor blade passing frequency and the spatial scale was half of the first order mode, representing smaller scale disturbances.