Geometry optimization of textured three-dimensional micro-thrust bearings

Papadopoulos, CI; Efstathiou, EE; Nikolakopoulos, PG; Kaiktsis, L

dc.contributor.author	Papadopoulos, CI	en
dc.contributor.author	Efstathiou, EE	en
dc.contributor.author	Nikolakopoulos, PG	en
dc.contributor.author	Kaiktsis, L	en
dc.date.accessioned	2014-03-01T02:02:11Z
dc.date.available	2014-03-01T02:02:11Z
dc.date.issued	2011	en
dc.identifier.issn	07424787	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29297
dc.subject	3-D micro-thrust bearings	en
dc.subject	multi-objective optimization	en
dc.subject	Navier-Stokes equations	en
dc.subject	rectangular texturing	en
dc.subject.other	3-D micro-thrust bearings	en
dc.subject.other	Bearing convergence ratio	en
dc.subject.other	Bearing loads	en
dc.subject.other	CFD codes	en
dc.subject.other	Computational costs	en
dc.subject.other	Convergence ratio	en
dc.subject.other	Design variables	en
dc.subject.other	Friction coefficients	en
dc.subject.other	Geometry optimization	en
dc.subject.other	Isothermal flows	en
dc.subject.other	Load carrying capacities	en
dc.subject.other	Micro thrust	en
dc.subject.other	Multi objective	en
dc.subject.other	Numerical solution	en
dc.subject.other	Optimal solutions	en
dc.subject.other	Optimal values	en
dc.subject.other	Optimization goals	en
dc.subject.other	Optimization procedures	en
dc.subject.other	Optimization studies	en
dc.subject.other	Optimization tools	en
dc.subject.other	Pareto dominance	en
dc.subject.other	rectangular texturing	en
dc.subject.other	Single objective optimization	en
dc.subject.other	Surface-texturing	en
dc.subject.other	Bearing capacity	en
dc.subject.other	Convergence of numerical methods	en
dc.subject.other	Friction	en
dc.subject.other	Geometry	en
dc.subject.other	Load limits	en
dc.subject.other	Multiobjective optimization	en
dc.subject.other	Navier Stokes equations	en
dc.subject.other	Optimal systems	en
dc.subject.other	Three dimensional	en
dc.subject.other	Viscous flow	en
dc.subject.other	Thrust bearings	en
dc.title	Geometry optimization of textured three-dimensional micro-thrust bearings	en
heal.type	journalArticle	en
heal.identifier.primary	10.1115/1.4004990	en
heal.identifier.secondary	http://dx.doi.org/10.1115/1.4004990	en
heal.identifier.secondary	041702	en
heal.publicationDate	2011	en
heal.abstract	This paper presents an optimization study of the geometry of three-dimensional micro-thrust bearings in a wide range of convergence ratios. The optimization goal is the maximization of the bearing load carrying capacity. The bearings are modeled as micro-channels, consisting of a smooth moving wall (rotor), and a stationary wall (stator) with partial periodic rectangular texturing. The flow field is calculated from the numerical solution of the Navier-Stokes equations for incompressible isothermal flow; processing of the results yields the bearing load capacity and friction coefficient. The geometry of the textured channel is defined parametrically for several width-to-length ratios. Optimal texturing geometries are obtained by utilizing an optimization tool based on genetic algorithms, which is coupled to the CFD code. Here, the design variables define the bearing geometry and convergence ratio. To minimize the computational cost, a multi-objective approach is proposed, consisting in the simultaneous maximization of the load carrying capacity and minimization of the bearing convergence ratio. The optimal solutions, identified based on the concept of Pareto dominance, are equivalent to those of single-objective optimization problems for different convergence ratio values. The present results demonstrate that the characteristics of the optimal texturing patterns depend strongly on both the convergence ratio and the width-to-length ratio. Further, the optimal load carrying capacity increases at increasing convergence ratio, up to an optimal value, identified by the optimization procedure. Finally, proper surface texturing provides substantial load carrying capacity even for parallel or slightly diverging bearings. Based on the present results, we propose simple formulas for the design of textured micro-thrust bearings. © 2011 American Society of Mechanical Engineers.	en
heal.journalName	Journal of Tribology	en
dc.identifier.doi	10.1115/1.4004990	en
dc.identifier.volume	133	en
dc.identifier.issue	4	en