Computational Fluid Dynamics Investigation of Hydrodynamic Journal Bearing Performance Using TiO₂-Based Nanolubricants

Hydrodynamic journal bearings are commonly used in high-speed rotating machines because they can support heavy loads, create low friction, and long service life. However, the performance of regular lubricants declines under tough operating conditions due to excessive heat and friction. This study looks at how well a hydrodynamic journal bearing works with SAE 20W40 engine oil that includes titanium dioxide (TiO₂) nanoparticles, using Computational Fluid Dynamics (CFD). A three-dimensional lubricant film model is created in ANSYS Fluent. In this model, the lubricant flow is steady, incompressible, and laminar. The effective thermo-physical properties of the nanolubricant are calculated using standard mixture models. The study evaluates how the concentration of nanoparticles and the journal's rotational speed affect hydrodynamic performance by analyzing pressure distribution, load-carrying capacity, temperature, frictional force, and lubricant flow characteristics. The CFD results show that adding TiO₂ nanoparticles improves the thermal conductivity and pressure generation of the lubricant. This leads to a higher load-carrying capacity and better heat dissipation compared to the base lubricant. Even though a small increase in viscosity causes a slight rise in frictional force, the overall performance of the bearing improves significantly due to better lubrication stability and thermal properties. The study concludes that TiO₂-based nanolubricants present a promising way to enhance the efficiency, reliability, and lifespan of hydrodynamic journal bearings in automotive and industrial rotating machinery.