Hydrodynamic lubrication of micro-textured surfaces: Two dimensional CFD-analysis

• Numerical study of hydrodynamic lubrication between parallel micro-textured surfaces.
• We determine maximum friction reduction by a single-phase flow varying the geometry.
• We analyse the pressure distribution to verify the possibility of cavitation.
• We find a value of micro-texturing depth maximising the probability of cavitation.

This paper provides a numerical study of the hydrodynamic lubrication between two parallel surfaces with micro-texturing. The two-dimensional Navier–Stokes equations for an isothermal incompressible steady flow have been considered as a suitable model. A wide variety of geometries characterised by different micro-cavity depth and width, and different gap values have been analysed in order to study the influence of these parameters on the drag force magnitude. A detailed analysis of flow velocity profiles and pressure distributions has been performed to study the forces acting on the textured surface, providing an explanation for the maximum drag reduction achievable with a single-phase lubrication fluid. Furthermore, results indicate that three regions exist, depending on the cavity depth, in which a different flow dynamics occurs and the cavities have a different influence on the drag force. Finally, an “optimal” value of the depth has been found, for which the pressure reaches a minimum value and the probability of cavitation is maximised.