不同转速下轴流泵压力脉动试验

Test Comparative Study on Impact of Different Revolving Speed on Pressure Fluctuation in Axial Flow Pump

针对某一轴流泵模型，分别在转速1450、1200、1000r／min下，通过试验手段对其关键测点进行了压力脉动测量。通过幅值分析得到，随着流量的增大，RMS值曲线在叶轮进口处呈先降低后升高的趋势，在叶轮出口和导叶出口处呈逐渐降低趋势，转速越高RMS值变化速率越快。从频域来看，叶轮进口在3个转速下主频都为[1-r频，并在1450r／min、1200r／min转速下还存在Fn、2Fn,3Fn等比较明显的频率成分；叶轮出口压力脉动的频率范围主要分布在0～8Fn，之间，在1450r／min、1200r／min转速下，其主频出现在（3～4）Fn之间，在1000r／min转速下，其主频往大频率方向有所偏移，主要集中在（4～6）Fn之间；导叶出口压力脉动的频率范围主要分布在0，12Fn之间，在1450r／min、l200r／min两个转速下，其主频出现在（4～6）Fn之间，在1000r／min转速下，其主频主要出现在（6．8）Fn之间．

Pressure fluctuation measurement was conducted on the key points in an axial flow pump operating at 1 450 r/min,1 200 r/min, 1 000 r/min, respectively based on test. According to amplitude analysis, the results showed that the RMS tends to decrease firstly and then increase with the increase of flow rate at the impeller inlet, and decline in outlet of impeller and outlet of vane. The RMS varies more quickly with higher revolving speed. In terms of frequency domain, the base frequency at three revolving speeds is blade frequency at the impeller inlet, at the same time there also exists such frequency components： F,~, 2Fn, 3Fn at revolving speeds of 1 450 r/min and 1 200 r/min. And at the impeller outlet, frequency domain ranges from 0 to 8F~ ; the base frequency appears in the range of 3Fn to 4F at revolving speeds 1 450 r/rain and 1 200 r/rain and shifts to higher frequency from 4F,~ to 6Fn at revolving speed of 1 000 r/min. While at the outlet of guide-vanes, frequency domain of pressure fluctuation ranges from 0 to 12Fn ; the base frequency appears in the range of 4F to 6F at revolving speed of 1 450 r/min and 1 200 r/rain, and turns into another range from 6Fn to 8Fn at revolving speed of 1 000 r/rain. The pressure fluctuation law was obtained with different revolving speeds and measuring points in the axial flow pump actual operation in the study, which provides reference for numerical simulation and lays a theoretical basis for weakening pressure fluctuation of the axial flow pump.