Experimental Investigation on the Effect of Velocity Anisotropy on Oil Film State under Different Surface Wettability Interface

Abstract

This study focuses on the utilization of surface modification technology to create glass disks with varying surface wettability. A measurement test bench for point contact lubrication film is employed to investigate the impact of changes in the angle between the velocities of the glass disk and steel ball on the state of the lubricating oil film at the interface. The results show that altering the surface wettability reduces the adhesive strength between the interface and the adjacent lubricant, leading to a decrease in the ultimate shear stress, and inducing interface slippage. When the rotational velocity of the disk matches the translational velocity of the ball and their trajectories are inclined at specific angles, the sliding velocity increases proportionally to the inclination angle, which contributes significantly to the thermal effect. Furthermore, when the velocity varies across the interface with differences in wettability, the contact zone forms a wedge-shaped gap and causes modifications in the oil film’s shape, including the formation of an inlet dimple and an inclined straight stripe. The dominant factor influencing the interface is the slip when the angle is acute, whereas the thermal effect plays a significant role when the angle is obtuse. This work is expected to provide a new strategy for elastohydrodynamic lubrication under surface wettability interfaces.