在线翻译

【 中文 】
压力脉动频域分析
如图11(a),11(b),11(c),11(d),11(e),11(f)分别由时域图经傅里叶变换得到对应的叶轮外缘、蜗壳第一断面、第四断面、第六断面和出口断面各监测点压力脉动频域图。叶轮转速为3600r/min，轴频fn=60Hz,叶频f=180Hz。从图a中可以看出叶轮外缘的各监测点压力了脉动主频为3倍轴频。峰值集中在叶频及其倍频段，并且随着频率增加所产生的能量下降明显。因叶轮掠过隔舌时，工作面和背面的交替变化出现脉动幅值。脉动幅值随着监测点距叶片工作面的相对位置发生变化，靠近工作面时脉动幅值增加，反之减小。由于P7的外置比较特殊，此处脉动振幅下降明显。如图b,c,d,e所示压力脉动幅值整体下降明显，主频从第一段面到第七断面逐渐增大。但在出口处主频又出现了明显减小。蜗壳内各监测点脉动频率均出现了明显的紊乱，可能由于蜗壳内侧气相堆积使得液相流动受阻，出现漩涡、回流等流动不稳定现象。这使得蜗壳内流动较为复杂，出现了低频脉动分量。
【 英语 】
Frequency Domain Analysis of Pressure Fluctuation
Fig. 11 (a), 11 (b), 11 (c), 11 (d), 11 (e), 11 (f) obtained the pressure fluctuation frequency domain diagrams of the corresponding monitoring points of impeller outer edge, volute first section, fourth section, sixth section and outlet section by Fourier transform. The impeller speed is 3600 r/min, the shaft frequency is fn=60 Hz, and the blade frequency is f=180 Hz. From figure a, it can be seen that the main frequency of the pressure fluctuation at each monitoring point on the outer edge of the impeller is 3 times the axis frequency. The peak value is concentrated in the blade frequency and its frequency doubling band, and the energy produced decreases obviously with the increase of frequency. When the impeller passes through the tongue, the fluctuating amplitude appears in the alternating change of the working face and the back. The fluctuation amplitude changes with the relative position between the monitoring point and the blade working face. The fluctuation amplitude increases when the monitoring point is near the working face, and decreases when the monitoring point is near the working face. Because of the special exterior of P7, the fluctuation amplitude decreases obviously here. As shown in figs. b, c, D and e, the pressure fluctuation amplitude decreases obviously as a whole, and the main frequency increases gradually from the first section to the seventh section. However, the main frequency at the exit has decreased significantly. The fluctuation frequencies of each monitoring point in the volute are obviously disordered. It may be that the accumulation of gas phase inside the volute hinders the flow of liquid phase and causes unstable flow phenomena such as swirl and reflux. This makes the flow in the volute more complex, and the low-frequency fluctuation component appears.