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Numerical and Experimental Investigations on Preload Effects in Air Foil Journal Bearings

Mahner, Marcel ; Li, Pu ; Lehn, Andreas ; Schweizer, Bernhard (2017)
Numerical and Experimental Investigations on Preload Effects in Air Foil Journal Bearings.
In: Journal of Engineering for Gas Turbines and Power, 140 (3)
doi: 10.1115/1.4037965
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

A detailed elastogasdynamic model of a preloaded three-pad air foil journal bearing is presented. Bump and top foil deflections are herein calculated with a nonlinear beamshell theory according to Reissner. The two-dimensional pressure distribution in each bearing pad is described by the Reynolds equation for compressible fluids. The assembly preload is calculated by simulating the assembly process of top foil, bump foil, and shaft. Most advantageously, there is no need for the definition of an initial radial clearance in the presented model. With this model, the influence of the assembly preload on the static bearing hysteresis as well as on the aerodynamic bearing performance is investigated. For the purpose of model validation, the predicted hysteresis curves are compared with measured curves. The numerically predicted and the measured hysteresis curves show a good agreement. The numerical predictions exhibit that the assembly preload increases the elastic foil structural stiffness (in particular for moderate shaft displacements) and the bearing damping. It is observed that the effect of the fluid film on the overall bearing stiffness depends on the assembly preload: For lightly preloaded bearings, the fluid film affects the overall bearing stiffness considerably, while for heavily preloaded bearings the effect is rather small for a wide range of reaction forces. Furthermore, it is shown that the assembly preload increases the friction torque significantly.

Typ des Eintrags: Artikel
Erschienen: 2017
Autor(en): Mahner, Marcel ; Li, Pu ; Lehn, Andreas ; Schweizer, Bernhard
Art des Eintrags: Bibliographie
Titel: Numerical and Experimental Investigations on Preload Effects in Air Foil Journal Bearings
Sprache: Englisch
Publikationsjahr: 2017
Verlag: ASME
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Journal of Engineering for Gas Turbines and Power
Jahrgang/Volume einer Zeitschrift: 140
(Heft-)Nummer: 3
DOI: 10.1115/1.4037965
Kurzbeschreibung (Abstract):

A detailed elastogasdynamic model of a preloaded three-pad air foil journal bearing is presented. Bump and top foil deflections are herein calculated with a nonlinear beamshell theory according to Reissner. The two-dimensional pressure distribution in each bearing pad is described by the Reynolds equation for compressible fluids. The assembly preload is calculated by simulating the assembly process of top foil, bump foil, and shaft. Most advantageously, there is no need for the definition of an initial radial clearance in the presented model. With this model, the influence of the assembly preload on the static bearing hysteresis as well as on the aerodynamic bearing performance is investigated. For the purpose of model validation, the predicted hysteresis curves are compared with measured curves. The numerically predicted and the measured hysteresis curves show a good agreement. The numerical predictions exhibit that the assembly preload increases the elastic foil structural stiffness (in particular for moderate shaft displacements) and the bearing damping. It is observed that the effect of the fluid film on the overall bearing stiffness depends on the assembly preload: For lightly preloaded bearings, the fluid film affects the overall bearing stiffness considerably, while for heavily preloaded bearings the effect is rather small for a wide range of reaction forces. Furthermore, it is shown that the assembly preload increases the friction torque significantly.

Fachbereich(e)/-gebiet(e): 16 Fachbereich Maschinenbau
16 Fachbereich Maschinenbau > Institut für Angewandte Dynamik (AD)
Hinterlegungsdatum: 08 Nov 2017 15:11
Letzte Änderung: 03 Jun 2018 21:29
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