间隙和转速对轴流压气机非定常叶顶泄漏流周向传播特性影响的实验研究

Experimental Study of Effects of Tip Clearance and Shaft Speed on Circumferential Propagation Characteristics of Unsteady Tip Leakage Flow

针对一台低速单转子轴流压气机,对不同间隙和转速下非定常叶顶泄漏流诱导的压力波的周向传播特性进行了实验研究。通过机匣壁面上沿叶片弦向和周向分布的动态压力传感器,测量压气机转子叶顶区域流场的压力信号;借助功率谱密度、滤波、空间傅里叶变换等方法,分析了非定常波动的频率特性、传播速度和周向模态数的变化。结果表明,小间隙时叶顶泄漏流波动强度减弱;转速不变时减小间隙或间隙不变时提高转速,都将使得相同流量系数时叶顶泄漏流的波动频率增大。对各间隙和转速组合,随压气机节流,传播速度增大,周向模态数减少.转速不变时减小间隙,将使得相同流量系数时的传播速度和模态数增大;对同一间隙的相同流量系数,转速改变对模态数和传播速度无明显影响。

The circumferential propagation characteristics of pressure wave induced by unsteady tip leakage flow（TLF） in a low-speed isolated axial compressor rotor have been experimentally studied with different tip clearances and shaft speeds.The pressure signal at the tip region of the rotor was collected with dynamic pressure sensors aligned in circum-direction and chord-direction on the casing.And the changes of frequency,propagation speed and mode orders of the pressure wave were analyzed by methods such as Power Spectrum Density（PSD）,filter,Spatial Fourier Transform（SFT） and so on.The results show that the unsteadiness of TLF is restrained when the tip clearance reduces.The reduction of tip clearance ata certain shaft speed and the improvement of shaft speed with a certain tip clearance will improve the frequency of the unsteadiness of TLF.As the compressor throttling,the speed of the rotating wave will increase and the mode orders will decrease withdifferent clearances and at different shaft speeds Decreasing clearance at a certain shaft speed will improve the propagation speed and mode orders of TLF unsteadiness at the same flow coefficient,but shaft speed has little effect on mode ordersand propagation speed when clearance and flow coefficient don’t change.