雷诺数对轴流压气机转子非定常流动的影响

针对某轴流压气机转子,结合地面试验采用5通道的数值模拟方法在两个海拔高度下对该转子进行数值模拟,分析雷诺数(Re)对压气机中非定常流动的影响。在地面条件下数值模拟绝对坐标系下的频率均落于试验旋转不稳定(RI)的驼峰频率带宽范围内。相对坐标系下相邻通道的数值监测信号互功率谱证明了压气机中周向扰动的存在。该周向扰动的产生是泄漏流与叶顶载荷分布周期性相互作用的结果。高空20 km下压气机中存在特征频率不同的多个周向扰动。此时在叶片近吸力面的尾缘处存在较大范围的流动分离区,由此引起的径向低能流体与叶顶间隙泄漏流相互作用,并共同影响叶顶载荷分布,引起低雷诺数下压气机流动非定常性周向传播。 

Impact of Reynolds number on unsteady flow in axial flow compressor rotor

Experimental measurements were conducted for an axial high-speed subsonic compressor rotor on the ground. Numerical investigations were carried out at two altitudes to explore the mechanism of circumferential propagation characteristic at different Reynolds number (Re). Results showed that, on the ground, rotating instability (RI) was measured near stall condition, which was characterized by a hump frequency band in the spectrum. Characteristic frequencies of numerical pressure signals were limited in the frequency band of RI on the ground. The spectrums of the neighboring passages indicated that the flow unsteadiness rotated in the compressor. The circumferential disturbance was result of the periodic interaction between the blade tip leakage flow and the blade tip load. At the altitude of 20 km, there were several circumferential disturbances with different characteristic frequencies in the compressor near stall condition. The radial flow from the hub to tip induced by the suction surface flow separation was dominant in the tip region. The blade tip load was influenced both by the radial flow and tip leakage flow, as a result of the circumferential disturbance at low Re.