Influence of blade tip clearance on pressure fluctuation of submerged axial flow pump
The blade tip clearance of the axial flow pump is the key factor that causes vortex interference and pressure fluctu-ation,and the excitation force and pressure impact received by the unit under different blade tip clearance are significantly different.In this paper,350ZQ-125 vertical submerged axial flow pump with high specific speed is taken as the research ob-ject,and RNG k-ε turbulence model is adopted to calculate the pressure fluctuation in the three key parts of the axial flow pump with different blade tip clearance under the designed flow conditions.The results show that the pressure fluctuation in the axial flow pump is mainly caused by the dynamic and static interference when the blade tip clearance is not considered.When the blade tip clearance is considered,the pressure fluctuation in the pump is influenced by the clearance leakage,low-frequency fluctuation appears in the inlet horn and the guide vane flow channel,and the fluctuation amplitude gradually de-creases with the increase of the clearance.The dominant frequency of the fluctuation in the impeller flow channel is 3 fn,with insignificant fluctuation amplitude variation.Proper blade tip clearance can reduce the pressure fluctuation at the impeller in-let and the guide vane outlet.
axial flow pumpblade tip clearancenumerical calculationpressure fluctuation
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