Hydraulic Axial Thrust in Multistage Centrifugal Pumps

An experimental and theoretical study is performed with a single stage pump. The influence of the flow rate, the axial displacement of the impeller, and annular seal clearances on the hydraulic axial thrust is investigated. Pressure distributions measured in the space between the impeller and the casing agree with those calculated by the Kurokawa-Toyokura method when the leakage flow is inward in the space. It is clarified that the method is sometimes not available for the outward leakage flow because of the large thickness of the boundary layer in the space. A computer program for calculating the axial thrust in multistage centrifugal pumps is developed based on the method and experimental results. Axial thrusts measured in prototype multistage pumps agree with the calculation.