某单级跨声速轴流压气机失稳过程试验

为了深入认识高负荷单级跨声速轴流压气机的失稳过程,揭示其不稳定流动现象的发生、发展及其诱导压气机失稳的物理本质,针对某单级跨声速轴流压气机开展试验研究,对整个失稳过程进行了稳态和动态试验测量.通过对原始信号进行低通滤波和FFT(fast Fourier transform)分析,结果表明:在失稳过程中,静子叶根区域首先出现大幅值、轴对称的轴向低频扰动,此时,该压气机50%叶高以下的加功能力有所下降,但整机并未完全失稳.由于该扰动具有频率低、轴对称、幅值大等典型特征,因此,将这一现象定义为局部喘振.随着流量进一步降低,该扰动会沿轴向和径向传播,最终发展到全叶高,此后,该扰动在转子叶尖区域诱发出旋转失速团,最终导致压气机完全失稳.

Experiment on the instability process in a one-stage transonic axial compressor

To fully understand the instability process and reveal the occurrence, development and essence of the unstable flow phenomena of one-stage transonic axial compressor with high loading, test investigation was carried out with both steady and dynamic measurements. The analysis was performed by the original signal, the low pass filtering and the FFT (fast Fourier transform) method. The results show that the large amplitude, low frequency axisymmetric axial disturbance appears firstly at the stator hub during the instability process. At that time, there is a decrease in the performance below 50% span of the compressor. But the compressor can still be operated. Meanwhile, considering the features of this disturbance such as low frequency, axisymmetricity, large amplitude, this kind of unstable flow phenomena, named as partial surge, is identified. Then, this disturbance spreads axially and radially with the further decrease of the mass flow. Next, this disturbance extend to the full span. Finally, it leads to the rotating stall cells at the rotor tip region, and the indicating the compressor reached the instability boundary.