Rotordynamic Developments For High Speed Multistage Pumps

Abstract

At present, the majority factor limiting the designer’s ability to predict the rotordynamic behavior of multistage centrifugal pumps is the availability of accurate input data for the forces acting on the rotor. Recent results are presented from an ongoing research project sponsored by the Electric Power Research Institute at Sulzer Brothers on the measurement of hydraulic forces on impellers of high energy pumps. The best available coefficients for seals and impeller forces, derived from the research, are applied to a typical four stage diffuser style pump. The application of swirl breaks to impellers is demonstrated. The results of the analysis is then compared to actual test data. The conclusions highlight the importance of including impeller hydraulic forces in the rotordynamic analysis, the potential of swirl breaks to significantly improve rotor stability and areas needing further research.