低速轴流压气机中气动旋转不稳定性和叶顶泄漏流脉动特性

为了探究气动旋转不稳定性和叶顶泄漏流脉动特性的关系，对一台1.5级低速轴流压气机进行了实验和数值研究.在转子顶部机匣上布置动态压力传感器，采集不同流量下叶顶的压力脉动信号，在小流量下捕捉到了旋转不稳定性的产生.通过锁相平均和方均根压力图谱，发现当叶顶泄漏流与相邻叶片发生干涉时叶顶流场脉动显著增强.对压气机转子进行全通道数值模拟，发现叶顶泄漏流在小流量下发生周期性振荡，且相邻流道间的压力脉动具有相位延迟，这诱导产生了一个具有多重频率的旋转压力波.通过频谱分析发现:脉动的叶顶泄漏流产生的旋转压力波与旋转不稳定性具有一致的频率特性，表明叶顶泄漏流的脉动对压气机中旋转不稳定性的产生具有重要作用. 

Aerodynamic rotating instability and fluctuated characteristics of tip clearance flow in low speed axial flow compressor

To investigate the relationship between aerodynamic rotating instability and fluctuated characteristics of tip clearance flow, experiment and numerical studies were conducted on a 1.5 stage low speed axial flow compressor. The rotating instability was detected through casing mounted dynamic pressure sensors. The phase-locked and root mean square(RMS) pressure contours showed that the interaction of tip clearance flow with the neighboring blade was the most likely cause of casing flow field fluctuation. From the calculated results of whole-annulus cascade, it is found that the tip clearance vortex structure oscillates periodically at low flow rate conditions. Furthermore, phase lag of pressure fluctuations exist between two neighboring passages, which induces a rotating pressure wave of multiple frequencies. The frequency characteristics of this rotating pressure wave caused by fluctuation of tip clearance flow are coincident with the frequency of rotating instability. This suggests that the fluctuation of tip clearance flow is the major contributor to the initiation of rotating instability.