缝隙引流叶轮离心泵空化试验研究

在额定转速、不同流量工况下,对带有缝隙引流叶轮和常规叶轮的低比转数离心泵进行空化试验,通过安装在待测试离心泵不同位置上的加速度传感器获得相应的振动加速度信号,进而分析2种叶轮离心泵的空化特征信号,对比2种离心泵的空化特性.试验结果表明:缝隙引流叶轮离心泵比常规叶轮离心泵有更好的抗空化性能;Q=26 m³/h时,在空化过程中3个振动测点处的加速度信号有效值均随有效空化余量的减小而增大,并且缝隙引流叶轮离心泵的振动弱于常规叶轮离心泵,说明振动加速度测试可有效监测空化发生前后信号的变化;在本次试验的多个测点中,出口处的振动测点对空化较为敏感,更适宜作为空化监测点.

Experimental study on cavitation performance of centrifugal pump with impeller having leading edge slots

The cavitation performance of a low specific-speed centrifugal pump with impeller having leading edge slots and the conventional one were measured at various flow rates; and the vibration acceleration signals were acquired by the acceleration sensors installed in various locations in the experimental pump casing; eventually the cavitation performance of these two kinds of impellers was compared and the obtained signals indicating the cavitation characteristics were analyzed. The experimental results turn out that a much better cavitation performance has been achieved with the impeller having leading edge slots comparing with the conventional one. After the RMS(root mean square)of the vibration acceleration signals obtained at the Q=26 m³/h condition being analyzed, it was shown that all the normalized energy of the vibration acceleration at three monitoring points increase with decreasing NPSH available; meanwhile, the vibration of the pump with the impeller having leading edge slots is less violent than that with the conventional impeller during the cavitating process. It suggests that the vibration acceleration acquired can monitor the change in the signals effectively before and after cavitation occurs. The signals picked up at the monitoring point near the outlet of the pump is more sensitive to cavitation state, thus this point is more suitable to be used as the cavitation monitoring site compared with the rest monitoring points in this experimental investigation.