Steady state characteristics and stability limits of oil lubricated journal bearings using titanium dioxide nanoparticles as lubricant additives

Abstract

The current work is presented to investigate the impact of titanium dioxide (TiO2) nanoparticle volume fraction and the nanoparticle aggregate sizes on the steady state characteristics and stability limits of journal bearings. A modified Krieger-Dougherty model is used to determine the viscosity of a TiO2 dependent nanolubricant with different TiO2 nanoparticle volume concentration and aggregate particle sizes. Dimensionless couple stress parameter values are calculated based on aggregate particle size and bearing radial clearance. The effects of the couple stress parameter on bearing's steady-state characteristics and dynamic response are studied. The results reveal that increasing the couple stress parameter increases the bearing load capacity as well as the bearing's stability limits. The aggregate TiO2 nanoparticle sizes have sensible effects on bearing characteristics and stability limits of the bearing.