贯流泵内部压力脉动特性的数值计算

Numerical calculation of characteristics of tubular pump internal pressure pulsation

压力脉动是影响贯流泵稳定运行的关键因素之一,本文采用大涡模拟对其内部流场进行分析总结,研究表明:压力脉动主要受叶轮旋转及动静相互干扰的影响;叶轮外缘与壁面间隙的存在,使小部分流体会从高压压力面流向低压吸入面出现回流,而加剧了压力脉动的影响,其幅值为进口压力脉动幅值的38倍;在大流量和小流量下压力脉动幅值均大于设计工况下的压力脉动幅值,导叶的整流特性减弱了叶轮压力脉动的影响;非设计工况下,在叶片进口边处,压力脉动幅频谱幅值最大,水力激振与叶轮旋转的影响相互叠加,在小流量下幅频谱幅值最大约为设计工况的1.5倍,在大流量下约为1.1倍。

Pressure pulsation is a key factor to stable operation of tubular pump.This paper presents an analysis and the following summary of the pressure pulsation on the basis of large eddy simulation data.Pressure pulsation is caused by two major factors,rotating impeller and stator-rotor interaction,and it is further enhanced by reverse flow in the gap between impeller and wall surface,i.e.the water flow from the blade pressure side of high pressure to the blade suction side of low pressure.The pulsation amplitude around this gap could be as great as 38 times of that at the pump inlet,and under large and small flow rates it is greater than the design values,while the flow management of guide vanes reduces the pulsation on the rotor.Under the off-design condition,the amplitude spectra of pressure pulsation shows the maximum intensity on the cross section upstream and close to the blades,where flow-induced vibration is intensified by pulsating forces of the rotating impeller.The maximum intensity of these spectra is roughly 1.5 and 1.1 times of the design value under the operating conditions of small and large flow rates,respectively.