Investigating linear and non-linear dynamic characteristics of textured journal bearings with slip boundary condition and pseudoplastic lubricants: a numerical study

External excitations and unbalanced rotor forces can increase vibration amplitudes and may also cause the breakdown of continuous liquid lubricant film in hydrodynamic journal bearings. The perfect isolation of the journal-bearing system from these undesirable forces and excitations are difficult. However, recent studies suggest that by utilizing advanced manufacturing techniques, smart coating materials, and highly efficient synthetic lubricants; one can improve the reliability of hydrodynamic lubricant film under such critical operating conditions. In the present study, authors observed the influence of micro-scale textures, low surface energy coatings with slip boundary condition, and pseudoplastic lubricants on the stability margin of hydrodynamic journal bearings. To perform this investigation, the unsteady thermo-hydrodynamic Reynolds equation with considering Elrod cavitation algorithm has been solved. Further, to observe variation in stability margin as compared to conventional bearings, the various dynamic characteristics such as stiffness and damping coefficients, critical mass and critical speed parameters, and journal center trajectory are examined in this study. The findings of the study reveal that slip-texture bearings lubricated with pseudoplastic lubricants are highly beneficial in improving the value of direct and cross stiffness coefficients. In addition, it has been observed that under unsteady operating condition, slip-boundary condition and micro-textures are increasing the isolation of the journal-bearing system and showing efficient control over the unstable motion of the rotating shaft.