Analyses of Hydrodynamic Forces on Centrifugal Pump Impellers

Citation

Adkins, Douglas Ray (1986) Analyses of Hydrodynamic Forces on Centrifugal Pump Impellers. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/X6KZ-W852. https://resolver.caltech.edu/CaltechETD:etd-03262007-111453

Abstract

It has been experimentally determined by previous investigators that hydrodynamic forces can cause a centrifugal pump impeller to whirl in a volute. The present work was undertaken to develop a theoretical model of the interactions that occur between an impeller and a volute, and to identify the source of the hydrodynamic forces. Experiments were then conducted to test the predictions of the model. The theoretical analysis presents a quasi-one dimensional treatment of the flow in the volute and accounts for the disturbance at the impeller discharge that is caused by the volute. The model also considers the lack of perfect guidance through the blade passages. Extending this model allowed for the calculation of hydrodynamic force perturbations that result when the impeller whirls eccentrically in the volute. These force perturbations were shown to encourage, rather than dissipate the whirling motion. The predictions of the model gave reasonable comparisons with the experimental data obtained in this study. Further, it was experimentally observed that pressure forces acting on the front shroud of the impeller could have a major influence on the hydrodynamic force perturbations acting on an eccentrically positioned impeller.

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