Improved centrifugal pump impeller design in terms of blade wrap and exit angles
WANG Yanyan1,2, ZHAO Weiguo1,2*, HAN Xiangdong1,2, ZHENG Yingjie1,2
1. School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2. Key Laboratory of Fluid Machinery and Systems, Gansu Province, Lanzhou, Gansu 730050, China
Abstract:Based on computational fluid dynamics(CFD)technology, numerical simulation of flow field in the whole centrifugal pump of KQW250-400 type was performed. At first, the original impeller blade design was altered according to blade design theory, and five impeller models were built by changing the blade wrap angle Φ and the blade exit angle β2. Then, the corresponding hydraulic perfor-mance curves and internal flow fields of the pumps with these different impeller models were obtained numerically. The results indicate that the impeller with blade wrap angle Φ=126° and exit angle β2 = 24° is the optimal and with the best performance, i.e. at the design flow rate Qd=550 m3/h, the calculated head and efficiency are 53.49 m and 87.66%, respectively. Based on the experimental data, the centrifugal pump with the original impeller is subject to a 49.10 m head and a 79.88% efficiency at the flow rate Q=551.381 m3/h in comparison with 51.84 m head and 85.65% efficiency at the flow rate Q=550.823 m3/h for the pump with the optimized impeller. As such the head and efficiency have increased by 2.74 m and 5.77%, respectively, under the design condition; especially, the efficiency curve with the optimized impeller of the centrifugal pump is all above the curve with the original impeller. This suggests that the overall performance of the centrifugal pump has been improved. This outcome is conducive to improving the economic benefits of pump utilization in buildings and subsequently reducing energy consumption.
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