混流泵水力模型空化诱导振动与噪声特性试验研究

Experimental investigation on cavitation induced noise and vibration characteristics of mixed-flow pump model

针对混流泵水力模型空化诱导过程中产生的振动与噪声问题,在大型泵综合性能试验台,采用物理试验方法,通过混流泵水力模型进出口、静动间等位置的振动测试,以及进出口4倍管径处的噪声测试,获取混流泵水力模型空化诱导过程的振动与噪声信号,并开展频谱分析及特征对比。结果表明:混流泵水力模型空化诱导过程出口处噪声明显高于进口处,进口处的辐射噪声先逐渐增大,在扬程下降约1%处达到极值后呈现减小趋势;出口处的辐射噪声先逐渐增大,达到极值后呈减小趋势,后又逐渐增大;进口处振动与噪声变化规律一致,在汽蚀余量比常压时下降20%~25%处出现极大值,可以通过振动来反映噪声的变化趋势;出口处振动噪声变化规律存在一定差异,振动强度峰值出现时汽蚀余量要小于出口处噪声声压级强度出现峰值时的汽蚀余量。所得结论可为混流泵减振降噪设计提供参考,对喷水推进泵空化状态的实时动态监测具有实际工程应用意义。

For the vibration and noise generated in the cavitation induction process of hydraulic model of mixed-flow pump,the vibration and noise signals of the cavitation induction process of hydraulic model of mixed-flow pump were obtained by using physical test methods in the comprehensive performance test bench for large-size pumps through vibration tests at the inlet and outlet of hydraulic model of mixed-flow pump,between stationary and moving components,and noise tests at the locations of inlet and outlet at four times pipe diameter.The frequency spectrum analysis and characteristic comparison were carried out.The results show that the noise at the outlet of the cavitation induction process of the hydraulic model of mixed-flow pump is significantly higher than that at the inlet,the radiated noise at the inlet gradually increases at first,and then decreases after reaching the extreme value where the head decreases by about 1%.The radiated noise at the outlet increases gradually,decreases after reaching the extreme value,and then increases gradually.The vibration at the inlet is consistent with the noise change law,and the maximum value appears at the point where the cavitation allowance decreases by 20%~25%.There are some differences in change of vibration and noise at the outlet,and the cavitation allowance when the peak vibration intensity appears is smaller than that when the noise pressure level intensity peak appears.The results can provide reference for vibration and noise reduction design of mixed-flow pump,and have practical engineering application significance for real-time dynamic monitoring of cavitation state of water jet propulsion pump.