Numerical analysis of pressure fluctuation of internal flow in submersible axial-flow pump
Zhang Yuxin1, Wang Xiuye2, Ding Peng2, Tang Xuelin2
1.Shanghai Richen Technology Co. Ltd., Shanghai 201800, China; 2.College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China
Abstract:The pressure fluctuation in flow field has important influence on the operation stability of axial-flow pumps. In order to precisely analyze the pressure fluctuation in submersible axial-flow pumps, the RNG k-ε turbulence model and SIMPLEC algorithm were adopted to investigate the three dimensional turbulent flow and the pressure fluctuation in an axial-flow pump. The calculated results show that the predicted performance curves of pump were in good agreement with the experiment. The maximum amplitude of the pressure fluctuation occurs at the inlet of the impeller, and the main frequency of the pressure fluctuation inside the pump is the same as the blade passing frequency when the pressure fluctuation behind the guide-vanes is dominated by low-frequency. From hub to tip of the blade surface, the low frequency components of the fluctuation decreases.On the pressure surface of the blade, the pressure fluctuation amplitude decreases from tip to hub and increases from inlet to outlet of the impe-ller. The fluctuation amplitude on the outer tip is 1.22 times higher than that on the hub at the inlet. On the suction surface, the pressure fluctuation amplitude on tip is 1.77 times of the hub at the inlet and is 0.92 times of the hub at the outlet of the impeller. The amplitude on the suction surface is significantly less than that on the pressure surface of the blade. At the inlet of the impeller, the maximum amplitude of the pressure fluctuation happens at 0.8Q flow rate which is about twice the value at the design flow rate. The above-simulated results can provide some references for further analyzing the pressure fluctuation of axial-flow pumps.
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