Investigation of the Integrated Model of Side Chamber, Wear-Rings Clearance, and Balancing Holes for Centrifugal Pumps

The characteristics of radial pressure distribution inside side chamber and leakage flow through balancing holes of centrifugal pumps are very important for accurately predicting the axial thrust produced by a balancing system. Therefore, a rapid and sufficiently accurate calculation method is required. An integrated model describing the characteristics of radial pressure distribution inside side chamber and leakage flow rate through balancing holes was established. In this model, the correction coefficient of liquid pressure at side chamber entrance and the discharge coefficient of balancing holes were obtained by experiment. The IS 80-50-315 type single-suction, single-stage, and cantilevered centrifugal pump with the structure of double wear-rings and balancing holes was employed as a model to investigate the characteristics of internal liquid flow of the balancing system. Under different pump flow rates, pump performance curves, radial pressure distribution inside side chamber, and leakage flow rate through balancing holes were examined with different balancing hole diameters. Afterward, the experimental data were compared with the predicted results. The comparisons showed a reasonable consistency. Consequently, according to detailed pump dimensions and operating conditions, the integrated model in current form is recommended for centrifugal pumps, which have low specific speed and are with balancing systems of double wear-rings and balancing holes. This can be used for the prediction of radial pressure distribution inside side chamber and leakage flow rate through balancing holes and can be used both at the design stage and nondesign stage.