CFD analysis of a journal bearing with a microgroove on the shaft
Abstract: Journal bearings are used in many applications. An increase of their load
carrying capacity and/or decrease of their losses may allow for savings of an
enormous amount of energy. One way to enhance the characteristics of journal
bearings is to modify the surface texture of the stator. The purpose of the
present study is to investigate the influence of a textured rotor on journal
bearing characteristics. Special attention is given to the losses and the
load carrying capacity under unsteady conditions.
Computational Fluid Dynamics is used to model the flow between the rotor and
the journal. The full Navier-Stokes equations are solved under unsteady
conditions with the commercial software ANSYS CFX 11. A two-dimensional
geometry is used to model the bearing. In order to make a simulation, a
separate rotor and stator are made and are attached to each other using a
rotor-stator interface. A journal bearing with a dimpled rotor is compared
with the same smooth journal bearing.
Firstly, a single geometry for the smooth journal bearing is used to evaluate
the possible numerical characteristics created by the interface. The results
illustrate no numerical difference between using a single geometry or using
two geometries. This result shows the high capability of the ANSYS CFX
software to handle moving objects in the flow and allow further investigation
on rotor texturing using this method.
Comparison between a dimpled rotor and smooth rotor shows no increase in load
carrying capacity of the journal bearing when thermal effects are not taken
into account.
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