含沙空化对轴流泵内压力脉动特性的影响

Effect of cavitation on pressure pulsation characteristics of an axial-flow pump under sand conditions

为了阐明含沙量、粒径、空化等因素对轴流泵内部压力脉动特性的影响,分别在清水、含沙水、清水空化及空化与泥沙磨损联合作用下,采用SST k-ω湍流模型对轴流泵内部压力脉动特性进行数值模拟分析,得到以下结论:泥沙的加入会加剧压力脉动,且促进空化的发展;叶轮出口处脉动系数均大于进口处,说明除空化外,叶轮与导叶的动静干涉是引发压力脉动的一个主要因素,且空化会增大压力脉动,对泵的振动造成不利影响;压力脉动引发的振动信号主要频率成分包括2.5 Hz,10 Hz和20 Hz,与水泵的转频2.5 Hz,叶频10 Hz及其二倍频20 Hz保持一致。

In order to clarify the influences of sediment concentration,particle size,cavitation and other factors on the internal pressure pulsation characteristics of an axial-flow pump,the SST k-ωturbulence model was adopted to do a simulation on the internal pressure pulsation characteristics under the conditions of clear water,sandy water,cavitation and cavitation under sand.The results show that the addition of sediment will increase the pressure pulsation and promote the development of cavitation.The pulsation coefficient at the impeller outlet is greater than that at the inlet.In addition to cavitation,the dynamic and static interference between the impeller and the guide vane is a major factor in causing pressure pulsation,and cavitation will further increase the pressure pulsation and adversely affect the vibration of the pump.The main frequency components of the vibration signal induced by pressure pulsation include those of 2.5 Hz,10 Hz and 20 Hz,which are consistent with the pump frequency of 2.5 Hz,the leaf frequency of 10 Hz and its second harmonic frequency of 20 Hz.