This study investigates the coupled thermo-tribological performance of aluminum matrix composite (Al7075–6 wt.% ZrB2) hydrodynamic journal bearings (HDJBs) lubricated with TiO2-enhanced SAE 20W40 nanolubricants. The research integrates experimental testing on a custom-built journal bearing rig with computational fluid dynamics (CFD) and finite element analysis (FEA) to evaluate hydrodynamic pressure distribution, frictional behavior, wear characteristics, thermal response, and deformation under varying loads and speeds. TiO2 nanoparticles (0.5–1.0 wt.%) were dispersed into the base oil via mechanical stirring and ultrasonication to achieve stable and uniform suspension. Experimental results showed that 1.0 wt.% TiO2 nanolubricant reduced the coefficient of friction by 42% and the wear rate by 65% compared with the base oil. CFD simulations predicted a maximum hydrodynamic pressure of 4.04 kPa at 1250 rpm, in close agreement with experimental measurements, with a deviation of less than 8%. Structural analysis confirmed minimal elastic deformation (< 0.001 mm) and safe stress levels (< 2.5 MPa), verifying mechanical reliability of the bearing under the tested conditions. The combined effect of ZrB2 reinforcement and TiO2 nanolubrication enhanced load-carrying capacity, film stability, and thermal dissipation, providing a pathway for lightweight, energy-efficient, and high-performance bearing systems for aerospace, automotive, and industrial rotating machinery applications.
Gaikwad et al. (Thu,) studied this question.