Change search
ReferencesLink to record
Permanent link

Direct link
Oil induced instability: analytic study and experimental verification on flexible rotor supported by a journal-bearing at one end
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
Vattenfall Research & Development.
2010 (English)In: Proceedings of the 8th IFToMM International Conference on Rotordynamics: September 12-15, 2010, KIST, Seoul, Korea, 2010Conference paper (Refereed)
Abstract [en]

Oil induced instability, is a frequently encountered phenomenon causing system instability for rotors supported by hydrodynamic journal-bearings. In this paper a flexible rotor, simply supported at one end and with oil lubricated journal-bearing at the other, is analytically modelled. The rotor system is modelled in two ways namely as a discrete system by finite element method (FEM) with nonlinear journal-bearing and as a lumped inertia system with linear journal-bearing. The analysed rotor-bearing system is a Bently Nevada Rotor Kit Model RK4 with Oil whirl/whip option. Results obtained from the simulation of the discrete rotor model with a nonlinear journal-bearing indicate at which rotational speed the oil induced instability (oil whirl) will occur. Campbell diagrams are shown for the lumped inertia rotor model with linear journal-bearing and the critical speeds are predicted. From the results the accuracy of the analytical speed-dependent bearing coefficients are evaluated. These coefficients were derived from the nonlinear bearing impedance descriptions by D. Childs. The bearing impedance descriptions method is a method valid for all L/D (length to diameter) ratios, and all journal eccentricities. The simulation time is significantly reduced by using a lumped inertia rotor model with linear journal-bearing. Critical speed obtained from Campbell diagram predicts a threshold speed of instability which is about 0.35% higher than that predicted by the discrete rotor model with a nonlinear journal-bearing. Compared with results collected from experiment, the simulation results predict a threshold speed of instability which is about 5.69% higher (linear analysis), or 5.36% higher (nonlinear analysis).

Place, publisher, year, edition, pages
Research subject
Solid Mechanics
URN: urn:nbn:se:ltu:diva-32869Local ID: 781f1850-5925-11df-b6eb-000ea68e967bOAI: diva2:1006103
IFToMM International Conference on Rotordynamics : 12/09/2010 - 15/09/2010
Godkänd; 2010; 20100506 (jealun)Available from: 2016-09-30 Created: 2016-09-30Bibliographically approved

Open Access in DiVA

fulltext(311 kB)0 downloads
File information
File name FULLTEXT01.pdfFile size 311 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Luneno, Jean-ClaudeAidanpää, Jan-Olov
By organisation
Mechanics of Solid Materials

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

ReferencesLink to record
Permanent link

Direct link