MULTISCALE ANALYSIS OF HYDRODYNAMIC JOURNAL BEARING
CONSIDERING THE EFFECT OF THE PHYSICALLY ADSORBED
BOUNDARY LAYER |
Kaicheng Gu , Shaojin Shao , Yongbin Zhang |
College of Mechanical Engineering, Changzhou University |
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ABSTRACT |
In itself, there is a very thin boundary layer physically adsorbed to the bearing surface. When the bearing
clearance is far larger than the thickness of this layer, the boundary layer effect in the bearing is negligible, and conventional
hydrodynamic lubrication theory just addresses on this topic. However, with the worsening of the operating condition, the
bearing clearance can be largely reduced and comparable to the thickness of the adsorbed boundary layer. For this case, the
effect of the adsorbed boundary layer must be considered. The present paper presents the multiscale analysis for the
performance of the hydrodynamic journal bearing in a wide range of bearing clearance considering the effect of the
physically adsorbed boundary layer. The calculation results indicate for how low bearing clearances the adsorbed boundary
layer effect should be incorporated. When the minimum bearing clearance is on the same scale with the thickness of the
adsorbed boundary layer, the hydrodynamic pressure in the bearing is locally largely increased by the effect of the adsorbed
boundary layer, and the load-carrying capacity of the bearing is correspondingly largely increased. This is particularly
significant for a strong fluid-bearing surface interaction. The study shows the great contribution of the physically adsorbed
boundary layer to the performance of the hydrodynamic journal bearing in the condition of low surface clearances, and
indicates the necessity of the multiscale analysis for this bearing. |
Key Words:
Adsorbed layer, Hydrodynamics, Journal bearing, Load, Multiscale, Pressure |
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