Moving textures: Simulation of a ring sliding on a textured liner

• The piston ring/liner contact is solved in the hydrodynamic lubrication regime.
• Textures (pockets in a square array) are set on the liner.
• A mass-conservative algorithm is used to treat cavitation.
• Several hundred texture configurations are considered.
• Up to 73% friction reduction is obtained for quasi-conformal contacts.

Numerical simulations of the ring/liner contact in which the liner exhibits a periodic texture (pockets) are reported. The mass-conservative Elrod–Adams model is used to treat cavitation, and the dynamics of the ring is considered with a linear mass that corresponds to actual engine compression rings. The results, computed at a Stribeck number of 10−3 and thus in the hydrodynamic lubrication regime, show that the ring profile determines whether pocketing is beneficial or not. For strongly non-conformal contacts pocketing is detrimental, but for quasi-conformal contacts friction reductions of up to 73% are predicted. The largest reduction in friction was obtained for textures consisting of close-packed arrays of circular pockets of diameter comparable to the size of the contact.