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| Cavitation characteristics of high-speed submersible axial-flow pump |
| CHEN Bin1,2,YANG Chen1*,ZHANG Hua3,WANG Yuan3,XIA Chenzhi4 |
| 1. School of Mechanical Engineering, Hefei University of Technology, Hefei, Anhui 230002, China; 2. School of Environmental Science Engineering, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China; 3. Nanjing Hegong Fluid Technology Co., Ltd., Nanjing, Jiangsu 211500, China; 4. South-North Water Transfer Jiangsu Water Source Co., Ltd., Nanjing, Jiangsu 210019, China |
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Abstract To study the cavitation characteristics of the axial-flow pump, a high-speed submersible axial flow pump with specific speed ns=700 was selected. Based on ANSYS CFX software, the curve of external characteristics was obtained, and it was found that the calculated results had errors with the experiment′s under the large flow condition. Using Rayleigh-Plesset cavitation model and SST turbulence model, the critical cavitation pressure was obtained. Analyzing the influence of inlet pressure and flow rate on cavitation volume fraction, the result shows that the critical cavitation pressure is increased with the increase of flow rate and rotation speed. The cavitation allowance in the design condition is 7.08 m and the critical pressure is 73 kPa. When the inlet pressure is below the critical pressure, se-rious cavitation occurrs in the pump. The cavitation position is mainly at the inlet rim of the blade′s suction surface and the separation position of the fluid before and after the maximum thickness. Since the pressure is larger than the vaporization pressure, there is no cavitation on the pressure surface. Increasing or decreasing the pump flow rate both lead to the aggravation of cavitation.Therefore, in engineering applications, the cavitation can be suppressed by increasing the inlet pressure of the pump and adjusting flow rate to the design value.
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Received: 06 December 2019
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