双吸离心泵压力脉动是影响水泵机组运行稳定性的关键因素之一。为研究叶轮形式对双吸离心泵压力脉动的影响,对5种方案的叶轮进行压力脉动同台试验。通过在吸水室和压水室壁面布置压力脉动传感器,采集各个测试流量下的压力脉动信号,并进行混频幅值和频谱分析,得到吸水室和压水室的压力脉动分布规律。结果表明:双吸离心泵普遍存在叶片通过频率、泵轴旋转频率和低于轴频的低频脉动成分。相对于传统双吸叶轮,两侧叶片交错布置后可改善压力脉动特性;调整叶片出口边形状,增加叶片后盖侧的包角,可明显降低压水室叶片通过频率的脉动幅值,减轻动静干涉的危害;采用长短叶片形式可改善叶轮进口流态,降低吸水室的压力脉动,改善小流量工况下压水室的压力脉动特性。
The pressure fluctuations in double-suction centrifugal pumps caused by internal flow are the primary sources of operation instability.In order to investigate the effects of impeller types on pressure fluctuations for double-suction centrifugal pumps,five impeller configurations are tested with the same experimental facilities.By arranging pressure transducers on the walls of suction chamber and spiral casing,fluctuating pressure signals are collected at various test flows.The signals in time domain are analyzed by using the FFT method and the frequencies are obtained.Results show that blade passing frequency,rotating frequency and some lower frequencies always exist in double-suction centrifugal pumps.Compared with the traditional impeller,the double suction impeller with bilateral blades staggered can reduce the level of pressure fluctuation.By adjusting the blade outlet shape and increasing the warp angle of the blade near the back shroud side,the amplitude of the pressure fluctuation at blade passing frequency becomes small.The impeller with splitter blades optimizes the flow state,lessens the pressure fluctuation in suction chamber region and improves the characteristic of pressure fluctuations in the spiral casing under small flow rate condition.