立式轴流泵装置压力脉动特性的试验

Experimental Analysis on Pressure Fluctuation of Multiple Conditions in Axial-flow Pumping System

为了分析不同流量时立式轴流泵装置进出水过流部件压力脉动特性,在进水流道出口段、出水流道渐扩段的壁面共设置7个压力脉动监测点进行实时测量,并采用快速傅里叶变换对时域数据进行处理。结果表明:进水流道出口段监测点P1,P2时域图为正弦波形,一个周期内波峰波谷数与叶片数相同,此时的脉动峰峰值远大于监测点P4,P6;出水流道渐扩段监测点P4,P6峰峰值从1.2Qbep到0.3Qbep先减小后增大,最优流量时脉动峰峰值最小。基于频谱分析,在不同流量时进水流道出口段各测点压力脉动的主频均为转频及其谐频,出水流道渐扩段监测点脉动幅值随流量的增大先减小后增大,且在最优工况时脉动幅值为最小值。转频对出水流道渐扩段处各监测点脉动频率的影响未呈现规律性。

In order to analyze characteristics of axial flow pump pressure fluctuation under different flow rates,seven pressure monitoring points were arranged on the pump section casing of the impeller inlet and outlet passage.The results show that the time domain diagram of pressure fluctuation of monitoring points at the impeller inlet was the normal sine shape and and the peak-peak value is much larger than the monitoring points P4 and P6.Time domains of pressure fluctuation at the impeller had four peaks and four valleys which were consistent with the number of the impeller blade.Based on the frequency domain diagram analysis,he main frequency of pressure fluctuation at the impeller inlet were all blade passing frequency and the harmonic frequency was its multiple frequency of the blade passing frequency.The fluctuation amplitude of the monitoring points of the outlet passage decreased first and then increased with the increase of the flow rate,and the amplitude of the pressure fluctuation is the smallest under the optimal operational condition.The regularity of the pressure fluctuation of the monitoring points P4,P6 is not found.