空化诱发的轴流泵振动特性实验研究

Experimental Study on Vibration Characteristics Induced by Cavitation of Axial-Flow Pump

运用LMS多通道振动噪声测试与动力学分析系统,对轴流模型泵最优工况流量下不同空化程度时的振动加速度进行了动态多点测量和分析,获得了振动加速度的特征频率以及低频、高频振动水平随汽蚀余量的变化规律。实验结果表明:轴频、叶频以及其高次谐波是泵振动的主要激励频率;空化诱发的振动主要为高频振动;随汽蚀余量的降低,低频振动和高频振动均呈现先上升后下降的趋势;高频振动比低频振动更易被阻尼力削弱,高频振动水平上升的拐点和空化引起泵能量性能下降的临界点相一致。

The vibration characteristics induced by cavitation of axial-flow pump at the best efficiency point were measured by using LMS sound ＆ vibration measurement. The characteristic frequency of vibration acceleration and relationship between vibration level and NPSH value were obtained. The experimental results show that the shaft frequency, blade frequency and their higher harmonic are main exciting frequency. The vibration induced by cavitation is mainly high frequency vibration. With the decrease of NPSH value, the level of high and low frequency vibration all increased first and then decreased. The high frequency vibration is easy weakened than low frequency vibration by damping. The inflection point of high frequency vibration rising curve is the same as the energy decreased critical uoint induced by cavitation.