导叶叶片数对多级离心泵压力脉动的影响

为了研究叶轮叶片数与导叶叶片数有无最大公约数对多级离心泵内部压力脉动的影响,在保证设计点外特性基本不变的前提下设计了4种不同叶片数的导叶,基于标准k-ε方程,应用CFX软件对M120多级离心泵的设计点工况进行定常和非定常计算,得到次级泵体叶轮和导叶内各监测点的压力脉动时域图和频域图.结果表明:数值模拟结果与外特性试验结果相吻合,证实了数值模拟的可行性.叶轮与导叶叶片数存在最大公约数的匹配方式对多级离心泵内部静压分布有影响,主要表现为正导叶进口边周向压力分布呈现周期性分布规律.导叶内部压力脉动主要受叶轮叶片数的影响,叶频在流动诱导振动中起主导作用.导叶叶片数对多级离心泵内部压力脉动影响较大,导叶内部压力脉动幅值随导叶叶片数的增加而增大.

Influence of guide vane blade number on pressure fluctuation in multistage centrifugal pump

In order to investigate the influence of common denominator of impeller and guide vane numbers on pressure fluctuation in the multistage centrifugal pump, four guide vanes with different blade numbers were designed and the hydrodynamic performance at the rated point remained unchangable. Based on the standard k-ε turbulence model, computational fluid dynamics software CFX was employed to carry out the numerical simulation calculations. Pressure fluctuations at monitoring points of impeller and guide vane in the second stage of the pump are obtained. The results show that the numerical simulation results coincide with experimental results, which proves the feasibility of the numerical simulation. The matching form of having the greatest common denominator of impeller and guide vane number has an obvious influence on the static pressure distribution in multistage centrifugal pumps, mainly for the periodic disciplinarian of circumferential pressure in the inlet of guide vane. The number of impeller is the main factor causing pressure fluctuation in the guide vane, and blade passage frequency has a great impact on the flow-induced vibration. The amplitude of pressure fluctuation increases with the increasing of the number of guide vane.