Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 1, 1990 | public
Journal Article Open

The Rotordynamic Forces on a Centrifugal Pump Impeller in the Presence of Cavitation


An experiment in forced vabration was conducted to study the fluid-induced rotordynamic force on an impeller whirling along a trajectory eccentric to its undeflected position in the presence of cavitation. The prescribed whirl trajectory of the rotor is a circular orbit of a fixed radius. The force measured is a combination of a steady radial force due to volute asymmetries and an unsteady force due to the eccentric motion of the rotor. These measurements have been conducted over a full range of whirl/impeller speed ratios at different flow coefficients without cavitation for various turbomachines. A destabilizing force was observed over a region of positive whirl ratio. The range of flow conditions examined for a centrifugal impeller in a spiral volute has been enlarged to include cavitation. Compared to the non-cavitating condition, cavitation corresponding to a head loss of three percent did not have a significant effect upon the unsteady force. However, a lesser degree of cavitation at the design point increased the destabilizing force for a particular set of whirl ratios.

Additional Information

Contributed by the Fluids Engineering Division for publication in the Journal of Fluids Engineering. Manuscript received by the Fluids Engineering Division May 15, 1989. The authors are indebted to the NASA George Marshall Space Flight Center, for continued sponsorship of this research under Contract NAS8-33108. One of the authors (R. Franz) would like to thank the Shell Foundation for providing a fellowship that sponsored his graduate studies.


Files (744.3 kB)
Name Size Download all
744.3 kB Preview Download

Additional details

August 21, 2023
October 13, 2023