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Pump instability phenomena generated by fluid forcesRotor dynamic behavior of high energy centrifugal pumps is significantly affected by two types of fluid forces; one due to the hydraulic interaction of the impeller with the surrounding volute or diffuser and the other due to the effect of the wear rings. The available data on these forces is first reviewed. A simple one degree-of-freedom system containing these forces is analytically solved to exhibit the rotor dynamic effects. To illustrate the relative magnitude of these phenomena, an example of a multistage boiler feed pump is worked out. It is shown that the wear ring effects tend to suppress critical speed and postpone instability onset. But the volute-impeller forces tend to lower the critical speed and the instability onset speed. However, for typical boiler feed pumps under normal running clearances, the wear ring effects are much more significant than the destabilizing hydraulic interaction effects.
Document ID
19860020709
Document Type
Conference Paper
Authors
Gopalakrishnan, S. (Borg-Warner Industrial Products, Inc. Long Beach, CA, United States)
Date Acquired
August 12, 2013
Publication Date
December 1, 1985
Publication Information
Publication: NASA. Lewis Research Center Instability in Rotating Machinery
Subject Category
MECHANICAL ENGINEERING
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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