Abstract
The mixed and fluid film lubrication characteristics of hydrodynamic journal bearings with surface wear dents are examined numerically. The mixed lubrication model is applied to the analysis, which is combined with the asperity-contact mechanism proposed by Greenwood and Williamson and the average flow model by Patir and Cheng, considering the effects of adsorbed film. The impacts of the depth of the dents and the operating conditions on the loci of the journal center, the asperity-contact and hydrodynamic fluid pressures, friction and the flow rate are discussed. The conclusions are as follows: i) In the mixed lubrication regime the dent of the bearing influences noticeably the contact and fluid pressures; ii) For smaller dents the pressure in contact and the friction coefficient decrease; for larger dents the pressure and the coefficient increase, and iii) As the dent becomes deeper, the flow rate increases.
