离心泵空化监测阈值确定方法研究

Experimental Research on the Method to Determine the Centrifugal Pump Cavitation Monitoring Threshold

空化监测阈值的确定是对水泵空化状态判别的关键环节,通过获取某离心泵进口声压和壳体振动信号,对其在额定转速1 440 r/m in,流量为90、100、110、120 m3/h的4种工况进行空化模拟试验研究。基于统计理论,提出利用参考频带能量的峰值确定空化阈值的方法。结果表明：在给定的参考的频宽下,试验测得的水声信号和壳体振动信号符合声压变化规律曲线,即随着空泡数的减小能量值先上升后下降。将试验得到的能量曲线峰值利用3σ原则确定其下限,再降低3~5 dB可作为空化阈值的参考。随着流量的增大,水声信号在参考频域能量的峰值先增大后减小,其对空化的敏感性大大强于壳体振动信号。

The determining of cavitation monitoring threshold is the key segment of distinguishing pump running state.A series of tests have been put into effect in a laboratory to simulate the cavitation,the signal of inlet sound pressure and enclosure vibration were acquired at 1440r/min,flow rate at 90, 100,110,120m3/h.The method to determine the cavitation monitoring threshold which based on statistic theory was posed by making use of reference frequency band energy.The results of cavitation experimental study showed that the inlet pressure sound and enclosure vibration signal of pump were followed uniformity by sound pressure rule at the reference frequency band,the energy value first rose then dropped along with cavity number diminishing;using 3σ principle,the energy curve peak lower limit value was firstly acquired by the experiment,then the value of decreasing 3～5dB was taken as the reference of cavitation threshold;the reference frequency band energy peak value of sound pressure first rose then dropped along with the increase of flow rate,and its cavitation sensitivity is stronger than the vibration signal.