Avoiding Starvation in Tribocontact Through Active Lubricant Transport in Laser Textured Surfaces
Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272 Renningen, Germany
Computational Multiphase Flow, Department of Mathematics, Technische Universität Darmstadt, Alarich-Weiss Straße 10, 64287 Darmstadt, Germany
Institut für Fertigungstechnik, Technische Universität Dresden, George-Bähr-Str. 3c, 01069 Dresden, Germany
Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Winterbergstr. 28, 01277 Dresden, Germany
Author to whom correspondence should be addressed.
Lubricants 2019, 7(6), 54; https://doi.org/10.3390/lubricants7060054
Received: 11 April 2019 / Revised: 16 June 2019 / Accepted: 17 June 2019 / Published: 25 June 2019
(This article belongs to the Special Issue Laser-Induced Periodic Surface Nano- and Microstructures for Tribological Applications)
Laser texturing is a viable tool to enhance the tribological performance of surfaces. Especially textures created with Direct Laser Interference Patterning (DLIP) show outstanding improvement in terms of reduction of coefficient of friction (COF) as well as the extension of oil film lifetime. However, since DLIP textures have a limited depth, they can be quickly damaged, especially within the tribocontact area, where wear occurs. This study aims at elucidating the fluid dynamical behavior of the lubricant in the surroundings of the tribocontact where channel-like surface textures are left after the abrasion wear inside the tribocontact area. In a first step, numerical investigations of lubricant wetting phenomena are performed applying OpenFOAM®. The results show that narrow channels (width of 10 μ
) allow higher spreading than wide channels (width of 30 μ ). In a second step, fluid transport inside DLIP textures is investigated experimentally. The results show an anisotropic spreading with the spreading velocity dependent on the period and depth of the laser textures. A mechanism is introduced for how lubricant can be transported out of the channels into the tribocontact. The main conclusion of this study is that active lubricant transport in laser textured surfaces can avoid starvation in the tribocontact.