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| Parametric study on improving the stability of axial-flow pumps with self-circulating casing |
| TONG Zhiting1,2,YUAN Ye1,2,ZHANG Zhimin3,ZHANG Chao1,2* |
| 1. Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, Tianjin University of Technology, Tianjin 300384, China; 2. National Demonstration Center for Experimental Mechanical and Electrical Engineering Education(Tianjin University of Technology), Tianjin 300384, China; 3. China Institute of Water Resources and Hydropower Research, Beijing 100038, China |
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Abstract In order to explore ways to effectively expand the stable operating range of axial-flow pumps, a single-channel steady numerical simulation of the self-circulating casing treatment was carried out on an axial-flow pump to analyze the influence of the circumferential coverage ratio, suction port position and throat height on the expansion and stability performance of water pumps, and to as well reveal the influence law and improvement mechanism of the self-circulating casing on the expansion and stability of axial-flow pumps. The results show that the self-circulating casing can effectively expand the flow range of the axial-flow pump, keeping the position of the suction port unchanged, increasing the circumferential coverage ratio and throat height can increase the flow margin, but the design point efficiency is reduced. The flow margin of the self-circulating casing with a throat height of 1.8 mm first increases and then decreases with the backward movement of the suction port position, and the efficiency first decreases and then increases, indicating that there is an optimal position above the blade tip. Within the scope of the study, the flow margin reaches a maximum of 5.93%, and the efficiency at the design point is reduced by a minimum of 1.12%. Through the self-circulating casing treatment, the area of the blockage area formed by the interaction between the blade tip leakage flow and the main flow above the blade tip is reduced, which is responsible for the extended flow range and increased efficiency of the axial-flow pump for small flow conditions. This study provides a reference for the expansion and stability of axial-flow pump under the end wall treatment of self-circulating casing.
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Received: 13 September 2022
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