Tribology of journal bearings under the influence of the temperature field and the kinematics of nano-additives in the lubricant

• Κύριος συγγραφέας: Συκιώτης, Αντώνιος
• Άλλοι συγγραφείς: Sykiotis, Antonios
• Γλώσσα: English
• Έκδοση: 2023
• Θέματα: Journal bearing; Lubrication; Nanoparticles; Finite difference method; Static analysis; Thermal analysis; Έδρανο ολίσθησης; Λίπανση; Νανοσωματίδια; Μέθοδος πεπερασμένων διαφορών; Στατική ανάλυση; Θερμική ανάλυση

Nowadays, lubrication is a rapidly growing practice among a significant number of industrial sectors owning to the fact that by applying substances known as lubricants in various machinery, it contributes to the reduction of the friction and wear that is developed during their operation. Specifically, friction and wear degrade the mechanical and functional properties of machinery causing their failure as well as generate heat energy which results in energy losses. One type of machine element whose functionality, capability and lifespan are greatly dependent on its lubrication is the journal bearing. Journal bearings are widely incorporated into a significant number of industrial equipment in order to prevent and reduce friction and wear between the contact surfaces of two relatively rotating components of the equipment. Throughout the duration of its operation, shearing stresses are developed and heat is generated which is transferred to the lubricant and hence the lubricant temperature increases and tribological properties such as its viscosity are modified leading to an overall degradation of it. Therefore, it is evident that the type of the applied lubricant as well as the lubrication conditions in which the journal bearing operates are crucial factors that have to be investigated and reviewed. It also has to be considered that among the diverse types of applied lubricants, the ones which contain a certain concentration of nanoparticles and are known as nanolubricants represent a major scientific interest in our days. The purpose of this study is to represent the lubrication properties and mechanisms of nanolubricants and to examine various research that have proposed methodologies to conduct statical and thermal analysis on a journal bearing in order to formulate and write a programming code where this analysis can be performed. This analysis is performed both for an analytical model as well as a numerical-based model, in each of which, a conventional lubricant and a nanolubricant are applied correspondingly with the aim of evaluating the variation of certain variables as well as validating the beneficial use of nanolubricants. The program is written in two separate files for each model type using the Matlab software, where the results are represented by value matrices and depicted by figures.