Balancing axial force in centrifugal pumps with pump out vanes

Application of pump out vanes is one of the solutions to reduce hydraulic axial force generated during centrifugal pump operation. This article presents the cause of the occurrence of hydraulic axial force and method of calculating pressure distribution at the rear of the impeller used to design pump out vanes properly. It illustrates results of pump out vanes CFD calculations and its validation by measurements. The article reviews the methods of reducing pressure on the rear wall of the centrifugal pump's rotor using pump out vanes. It presents empirical formulae allowing calculation of pressure depending on the geometrical parameters of the blades. The article presents various design solutions of pump out vanes.