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Influence of blade number on internal and external characteristics of mixed flow pump as turbine |
YANG Sunsheng, ZHOU Cheng*, SHAO Ke, FANG Tian |
National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China |
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Abstract In order to study the influence of the number of blades on the characteristics of the mixed flow pump work as turbine, the flow field simulation software ANSYS CFX was applied to numerically simulate the pump as turbine with the number of blades of 6, 7, 8, 9, 10, 11, 12, respectively, under the condition that other main geometric parameters of the impeller remained unchanged. The external characteristic curves, internal pressure field, velocity streamline field and turbulent kinetic energy distribution of the mixed flow pump work as turbine with different number of blades were obtained. By comparing and analyzing the simulation results, the influence law of blade number on mixed flow pump as turbine was obtained. The results show that the number of blades has a certain influence on the head and shaft power of the mixed flow pump as turbine, and the turbine efficiency is the highest when the number of blades is 8. The analysis of internal flow field shows that with the gradual increase of the number of blades, the restriction ability of the blades to the fluid is strengthened. The vortex area at the inlet of the impeller is gradually reduced, and the internal flow is improved. The more the number of blades is, the more obvious the turbulence concentration phenomenon is. The smaller the turbulent kinetic energy at the blade inlet, the more uniform the turbulent kinetic energy distribution. The excessive number of blades is not conducive to the improvement of turbine performance of mixed flow pump, that is, the optimal number of blades Z=8 makes the turbine performance reach the best.
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Received: 13 April 2022
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