On the wear of dynamically-loaded engine bearings with provision for misalignment and surface roughness

Abstract

Abstract A computational model is developed to assess the effect of wear on the performance of an engine bearing. The model takes into account the variation of the film thickness under dynamic loading due to the wear of the bearing surface and shaft misalignment. The model adopts the mass-conservative cavitation algorithm to account for cavitation. To consider the surface roughness, the average flow model for the hydrodynamic pressure and the Kogut and Etsion model for the elastic-plastic contact pressure are implemented. A method for assessment of wear over long-term operation of an engine bearing to avoid failure is provided. To gain insight, results of a series of simulations with illustrative examples are presented. The simulations shows that the contact pressure is much smaller than the hydrodynamic pressure. The wear is directly related to the contact pressure, i.e. the surface roughness and the film thickness. The film thickness tends to remain nearly the same regardless of the surface roughness due to the much small contact pressure. Therefore, a small reduction of the surface roughness on the bearing surface decreases wear considerably.