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The Effects of Vapor/Gas Bubbles on the Rotordynamic Forces in Bearings

d'Auria, Fabrizio and d'Agostino, Luca and Brennen, Christopher E. (1996) The Effects of Vapor/Gas Bubbles on the Rotordynamic Forces in Bearings. In: Cavitation and Gas-Liquid Flows in Fluid Machinery and Devices. Fluids Engineering Division. Vol.FED-23. No.236. American Society of Mechanical Engineers , New York, pp. 337-343.

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This paper presents an anylytical investigation of the effects that vapor/gas bubbles can have on the fluid-induced rotordynamic forces in a liquid-filled annulus between a cylindrical rotor and a surrounding cylindrical stator. It is demonstrated that such cavitation (vaporous or gaseous) can have important consequences in altering the rotordynamic characteristics of devices such as long journal bearings or long squeeze-film dampers. A linearized analysis which includes bubble dynamic effects is used to evaluate the rotordynamic effects caused by a small amplitude whirl motion of the rotor in both the high and low Reynolds number regimes of fluid motion. In the former case the Euler equations for a bubbly mixture are employed while, in the latter, a modified Reynolds lubrication equation is used. These are combined with a Rayleigh-Plesset analysis of the bubble dynamics which includes various bubble damping effects. It is shown that, in certain parametric regimes, the normal and tangential fluid-induced rotordynamic forces acting on the rotor can deviate substantially from their classical forms in single-phase flow.

Item Type:Book Section
Additional Information:This work has been supported by the Italian Ministry of Universities and Scientific Research and by the Office of Naval Research under grant number N-00014-91-K-1295.
Funding AgencyGrant Number
Italian Ministry of Universities and Scientific ResearchUNSPECIFIED
Office of Naval Research (ONR)N-00014-91-K-1295
Series Name:Fluids Engineering Division
Issue or Number:236
Record Number:CaltechAUTHORS:DAUcglffmd96
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94
Deposited By: Christopher Brennen
Deposited On:24 Sep 2004
Last Modified:02 Oct 2019 22:16

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