Theoretical Analysis and Experimental Research of Surface Texture Hydrodynamic Lubrication

Abstract

The research on surface texture is developing from single macro-texture to composite micro-nano texture. The current research on the anti-friction mechanism and theoretical models of textures is relatively weak. Studying the characteristics of different types of surface textures and determining the applicable working conditions of each texture is the focus of current research. In this paper, a mathematical model of hydrodynamic lubrication is established based on Navier–Stokes equations. The FLUENT software is used to simulate and analyze the four texture models, explore the dynamic pressure lubrication characteristics of different texture types, and provide data support for texture optimization. The key variable values required by the mathematical model are obtained through the simulation data. The friction coefficient of the texture under different working conditions was measured through friction and wear experiments, and the mathematical model was verified by the experimental results. The research results show that circular texture is suitable for low to medium speed and high load conditions, chevron texture is suitable for medium to high speed and medium to high load conditions, groove texture is suitable for high speed and low load conditions, and composite texture is suitable for high speed and medium to high load conditions. Comparing the experimental results with the results obtained by the mathematical model, it is found that the two are basically the same in the ranking of the anti-friction performance of different textures, and there is an error of 10%−40% in the friction coefficient value. In this study, a mathematical model of hydrodynamic lubrication was proposed, and the solution method of the optimal surface texture model was determined.

Unraveling Water-Based Lubrication with Carbon Dots of Asphaltene Origin

“…And, at higher sliding speeds, the primary friction mechanism becomes hydrodynamic lubrication from a fully formed fluid film. 32 Interestingly, all ACD loadings substantially reduce the friction factor of water in the boundary regime (surface contact dominated), pointing to their beneficial use as nanoadditives for water-based lubricants. Using 4 wt % of ACD, 8 wt % of 5 nm silica, and 1 wt % of 20 nm silica, demonstrating the most effective friction-reduction formulation within each nanofluid group, the high boundary friction factor of pure water (∼0.65) decreases to 0.26, 0.36, and 0.45, respectively.…”

“…As the speed increases, the entraining fluid increases the normal pressure, causing the surfaces to separate and revert to the mixed lubrication regime. And, at higher sliding speeds, the primary friction mechanism becomes hydrodynamic lubrication from a fully formed fluid film …”