CFD analysis of a journal bearing with a microgroove on the shaft

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.Validerat; 20101217 (root