B. Fritz, B. Scheichl:
"A comprehensive cylinder-lubrication model for reciprocating compressors";
Talk: 12th EFRC Conference, Warsaw, Poland (invited); 2021-08-24 - 2021-08-26; in: "12th EFRC Conference - August 24-26 2021 - Warsaw, Poland", H. Steinrück (ed.); European Forum for Reciprocating Compressors e.V., Dresden, Germany (2021), ISBN: 978-3-200-07873-4; 237 - 246.
Cylinder lubrication is common practice in the compressor industry to significantly reduce wear and friction of the rider and piston rings. Whereas "starved" lubrication shortens the lifetime of these rings, over-lubrication adds little benefit while potentially giving rise to additional problems regarding the downstream components due to oil carryover.
Given the substantial lack of viable alternatives, it is state-of-the-art to lube compressors according to basic empirical guidelines. These disregard system-specific parameters such as clearance, piston assembly, oil viscosity, etc. and provide no guidance for an optimal lube strategy (e.g. with respect to the timing of lube injection).
This work provides a detailed look into the hydrodynamic lubrication of the rider and piston rings on an entirely rational basis. Also, it sheds light on what constitutes an optimal lube strategy - something that is almost impossible to pursue by purely experimental means. Thus, a comprehensive simulation model has been developed that accounts for the mutual interactions between the oil film, the compressed gas, the piston and rider rings, the piston motion, the elastic deflection of the piston rod, and the crosshead dynamics. This model for the first time enables a detailed insight into the specific conditions of cylinder lubrication and opens a window of opportunity for a more reliable compressor operation, hence at reduced lube rates and thus maintenance costs.
CFD, elasto-hydrodynamic lubrication, minimum lubrication, piston rings, reciprocating compressors, rider rings, starved lubrication
https://publik.tuwien.ac.at/files/publik_297733.pdf