Abstract
In the recent years, the efficacy of utilizing sapphire outer rings as a viable tool for experimentally observing oil flows within rolling bearings has been demonstrated. However, in previous studies, such approach was applied under fully-flooded lubrication conditions exclusively. This paper presents the outcomes of observations and measurements conducted under oil-bath lubrication conditions of a vertical-axis Tapered Roller Bearing (TRB). The experimental work encompasses four operational speeds ranging from 1000 min−1 to 2500 min−1, and two oil levels, i.e. 10% and 100% of the bearing width. Pictures were captured using an High-Speed Camera (HSC) for a qualitative inspection. Particle Image Velocimetry (PIV) measurements were conducted for a quantitative assessment of the oil velocity fields. The findings reveal specific lubricant flows, highlight aeration, and show particular vorticity patterns that intensify with increasing speed. These experimentally obtained results align with Computational Fluid Dynamics (CFD) simulations conducted using a specially developed model in OpenFOAM®, leveraging a solver that accounts for aeration.