Current Projects
Grease Prognostics: Remaining Grease Life (PhD Candidate: Femke Hogenberk)
Currently, the remaining useful life of grease in a bearing cannot be accurately predicted. The aim of this project is to develop a model which combines concepts and theories in fluid mechanics, thermodynamics and rheology with experiments to predict the remaining grease life in bearings operating at low and medium temperatures. Thermodynamic characterization of grease lubrication mechanisms such as “grease bleed” is studied via the evolution of yield stress, bleed rate and oil content of the grease.
Film Thickness in Grease Lubricated Roller Bearings (PhD Candidate: Min Gao)
This research focuses on understanding the lubrication mechanism in a grease lubricated roller bearing. In the contact region, film thickness model for a cylindrical roller bearing (CRB) as a function of grease properties and operating conditions is developed. Outside the contact region, the replenishment mechanism in a CRB is investigated.
Oil Transport in Functional Polymer Brushes for Advanced Grease Lubrication (PhD Candidates: Sander Reuvekamp, Vincent Siekman and Luciana Buonaiuto)
In bearings, the physical mechanisms governing the slow continuous release of oil from the grease reservoir towards the rolling track is poorly understood. Here, we study the driving and resistive forces governing this oil bleeding mechanism, to improve the reliability and control of lubrication processes. Well-defined polymer brushes are used as a model surface to quantify the relative influence of oil transport within and above the system.
On the Mechanical Aging of Lubricating Greases at the Inlet of Roller Bearing Contacts (PhD Candidate: Robert Jan Meijer)
Low Friction Grease (PhD Candidate: Omid Ghaffarinejad)
Grease Base Oil Efficiency (Researcher: Jorn Dokter)
In grease lubricated bearings, grease life dominates bearing performance. Oil separation (bleed) from grease plays a major role in grease lubrication. To extend grease life—and thus, bearing life—control of the bleed rate as well as an efficient base oil is very important (minimum oil for maximum lubrication). Therefore, it is crucial to study the impact of oil chemistry on bleed and investigate what makes an efficient base oil.
Completed Projects
- Film thickness in grease lubricated ball bearings
- Thermo-mechanical aging of grease during churning
- Grease base oil evaporation model
- Wear model for grease lubricated bearings
- On rheology film-build-up and water in grease lubricated bearings
- Lubrication of railway switches
- On the mechanical aging of lubricating greases
- Grease bleed model