1. Experimental Validation of a Mixed-Lubrication Regime Model for Textured Piston-Ring-Liner Contacts
- Author
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Sorin-Cristian Vladescu, Francisco J. Profito, Tom Reddyhoff, Daniele Dini, Engineering & Physical Science Research Council (EPSRC), and Ford Motor Company
- Subjects
Technology ,Materials science ,Polymers and Plastics ,Materials Science ,Flow (psychology) ,AVERAGE FLOW MODEL ,Materials Science, Multidisciplinary ,02 engineering and technology ,Surface finish ,surface texture ,mixed lubrication ,Reciprocating motion ,0203 mechanical engineering ,HYDRODYNAMIC LUBRICATION ,ROUGHNESS ,Fluid dynamics ,Piston ring ,piston rings ,Simulation ,Science & Technology ,FRICTION FORCE ,Metals and Alloys ,modeling ,CAVITATION ,Mechanics ,021001 nanoscience & nanotechnology ,020303 mechanical engineering & transports ,Mechanics of Materials ,SIMULATION ,STRIBECK CURVE ,Ceramics and Composites ,Lubrication ,JOURNAL BEARINGS ,0210 nano-technology ,Asperity (materials science) ,Tribometer - Abstract
Recent experiments have shown that automotive piston-liner friction may be reduced by up to 50 % if the surface of the liner is laser textured with certain configurations of micro-pockets. It is important to model this behavior to understand and optimize the friction reduction mechanisms that are occurring. However, until now, very few models that predict the lubrication performance of textured surfaces have been successfully validated against experimental data. This is because of the requirement for them to: (1) reproduce experimental configurations with a certain degree of fidelity, (2) conserve mass properly, and (3) account for transient, boundary lubrication conditions. To address this, the current paper presents a comparison between the results from a numerical model, which fulfils these criteria, and an experimental test rig operating under the same conditions. The mathematical modeling is based on the averaged Reynolds’ equation with Patir and Cheng’s flow factors and the p − θ Elrod–Adams mass-conserving cavitation model. Simultaneously to the fluid flow solution, the contact pressures that arise from the asperity interactions are also included into the calculations through the well-known stochastic Greenwood and Tripp model for rough contacts. The experimental data is produced using a reciprocating tribometer, whose contact conditions are closely controlled and accurately mimic those found in an automotive piston–liner conjunction. Data is presented in terms of friction force versus stroke angle, and the similarities and differences between the model and experiment are discussed.
- Published
- 2017
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