Author(s): R S Xie; F P Tang; F Yang; C Xiang

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Keywords: Axial flow pump; Blade root clearance; Hydraulic characteristic; Numerical simulation

Abstract: The clearance located on the blade root is almost 10–20 times that at the tip in an adjustable axial flow pump; the flow in the blade root clearance has an obvious impact on the hydraulic characteristic in pump systems. To research the effect of blade root clearance on hydraulic characteristic in an axial flow pump system, a vertical axial flow pump system is investigated by numerical simulation and experiment. After accounting for the root clearance, the result shows high precision under large and design flow conditions. The simulation result shows that, with the effect of the blade root clearance, the velocity distribution from hub to shroud tends to worsen, and the streamline near the blade root changes greatly; under the same flow condition, the flow far away from the hub in the cascade increases, the work ability of the blade reduces, and the head falls sharply. In this paper, with only 0.5 mm clearance present, 2.9 % of the blade surface area is lost, the head decreases by 7.86 %, shaft power decreases by 6.35 %, and the efficiency drops from 76.04 % to 74.82 %. The conversion formula between the pump station with and without gap clearance is obtained by theoretical derivation.

DOI: https://doi.org/10.1088/1755-1315/163/1/012123

Year: 2017