Preliminary design of new lubricants featuring inhomogeneous or anisotropic viscosity

Bletsos, Georgios; Μπλέτσος, Γεώργιος

dc.contributor.author	Bletsos, Georgios	en
dc.contributor.author	Μπλέτσος, Γεώργιος	el
dc.date.accessioned	2020-04-15T12:51:01Z
dc.date.available	2020-04-15T12:51:01Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/50194
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.17892
dc.rights	Αναφορά Δημιουργού-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nd/3.0/gr/	*
dc.subject	Λίπανση	el
dc.subject	Συνεκτικότητα	el
dc.subject	Εξελικτικοί αλγόριθμοι	el
dc.subject	Υπολογιστική ρευστομηχανική	el
dc.subject	Μοριακή δυναμική	el
dc.subject	Lubrication	en
dc.subject	Viscosity	en
dc.subject	Evolutionary algorithms	en
dc.subject	Computational fluid dynamics	en
dc.subject	Molecular dynamics	en
dc.title	Preliminary design of new lubricants featuring inhomogeneous or anisotropic viscosity	en
dc.title	Προκαταρτικός σχεδιασμός νέων λιπαντικών με ανομοιογενή ή ανισότροπη συνεκτικότητα	el
heal.type	bachelorThesis
heal.classification	Computational fluid dynamics	en
heal.classification	Molecular dynamics	en
heal.classification	Optimization	en
heal.classification	Computational tribology	en
heal.language	el
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2019-07-05
heal.abstract	Friction accounts for approximately 15% of fuel energy losses in internal combustion engine vehicles. To reduce it, new lubricants should be designed. Inspired by studies and observations on ionic liquids and liquid crystals, their inhomogeneous and anisotropic characteristics are studied as potential beneficial attributes to lubrication. In this diploma thesis, inhomogeneity is emulated in the continuum domain by introducing an inherently inhomogeneous viscosity in the Navier-Stokes equations. Viscosity parameterization schemes are programmed and implemented in the OpenFOAM environment. Using an evolutionary algorithm, implemented within the generic optimization platform EASY, optimal viscosity profiles leading to a potential improvement in friction performance are identified for a converging hydrodynamic slider. Parametric studies are carried out to further understand the complexities involved in such lubricating methods. In the anisotropic approach, a tensorial viscosity description is adopted. The Navier-Stokes equations are adapted accordingly and in the OpenFOAM environment. The model is then coupled with an evolutionary algorithm targeting to identify the impact of the tensor's terms on lubrication performance. The study is then extended to the nano-scale. Specific particle typologies, featuring optimized viscosity variations, as identified in the continuum domain, are selected using coarse grain molecular dynamics simulations. Through the appropriate tuning of the particles' properties, viscosity inhomogeneity is achieved and friction is reduced compared to a homogeneous case.	en
heal.sponsor	Major part in this diploma thesis was carried out in the premises of Toyota Motor Europe in Brussels, Belgium, during a 9 month long internship.	en
heal.advisorName	Giannakoglou, Kyriakos C.	en
heal.advisorName	Gkagkas, Konstantinos	en
heal.committeeMemberName	Γιαννάκογλου, Κυριάκος Χ.	el
heal.committeeMemberName	Μαθιουδάκης, Κωνσταντίνος	el
heal.committeeMemberName	Αρετάκης, Νικόλαος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Μηχανολόγων Μηχανικών. Τομέας Ρευστών. Εργαστήριο Θερμικών Στροβιλομηχανών	el
heal.academicPublisherID	ntua
heal.numberOfPages	92 σ.	el
heal.fullTextAvailability	true