Numerical analysis of the influence of vortex on the pressure pulsation in axial flow pump system based on the CFD

Asian Working Group- IAHR's Symposium on Hydraulic Machinery and Systems

Song, X.J.^1 ; Liu, C.^1

School of Hydraulic Energy and Power Engineering, Yangzhou University, Yangzhou, Jiangsu

225009, China^1

关键词: Characteristics of pressures;    Frequency domains;    Guide vane outlets;    K-epsilon turbulence model;    Low pressure zone;    Maximum amplitude;    Pressure fluctuation;    Pressure pulsation;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/163/1/012106/pdf
DOI  :  10.1088/1755-1315/163/1/012106

来源: IOP

【 摘 要 】

The pressure pulsation is one of the main causes of vibration and noise in axial flow pump, in order to study the mechanism of pressure fluctuation induced by vortex, several pressure pulsation monitoring points were stalled at the bottom of the pump sump, the horn mouth, the impeller inlet and outlet, the outlet of the guide vane. The flow rate of 1.2Qd ( Q=38.4L/s) was selected at the speed of 2200r/min. Realizable k- epsilon turbulence model is adopted with setting up different time calculation methods by using CFX software. Changing the time step, unsteady calculation of axial flow pump device is carried out, and the pressure values of different monitoring points at different time are obtained. The frequency domain characteristics of different feature sections are obtained by FFT. The results show that the vortex position at the bottom of the inlet of the flare tube is consistent with the position of the low pressure zone, and the main frequency of the pressure fluctuation is twice of the frequency of the impeller. The characteristics of pressure fluctuation at the bottom of the inlet of the horn are consistent with the experimental results. Under the influence of impeller rotation, the main frequency of pressure fluctuation at the inlet and outlet of impeller is 4 times of the impeller rotation frequency. The main frequency of pressure fluctuation at the guide vane outlet is 3 times of that of the impeller. The amplitude of pressure fluctuation increases gradually from the bottom of inlet to the inlet of impeller. On the whole, the maximum amplitude of pressure fluctuation is at the inlet of impeller, and the maximum amplitude of pressure fluctuation occurs at the center of the vortex belt. The Cp value of the pressure fluctuation at the center of the vortex belt is about 1.8-2 times of the Cp value of the pressure fluctuation at the non-central point.