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Modified Reynolds equation for aerostatic porous radial bearings with quadratic forchheimer pressure-flow assumption / Rodrigo Nicoletti in Transactions of the ASME . Journal of tribology, Vol. 130 n°3 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 130 n°3 (Juillet 2008) . - 12 p. Titre : Modified Reynolds equation for aerostatic porous radial bearings with quadratic forchheimer pressure-flow assumption Type de document : texte imprimé Auteurs : Rodrigo Nicoletti, Auteur ; Zilda C. Silveira, Auteur ; Benedito M. Purquerio, Auteur Année de publication : 2008 Article en page(s) : 12 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Pressure  Flow  (Dynamics)  Porous  materials  Bearings  Equations  Stress  Stiffness Résumé : Aerostatic porous bearings are becoming important elements in precision machines due to their inherent characteristics. The mathematical modeling of such bearings depends on the pressure-flow assumptions that are adopted for the flow in the porous medium. In this work, one proposes a nondimensional modified Reynolds equations based on the quadratic Forchheimer assumption. In this quadratic approach, the nondimensional parameter Φ strongly affects the bearing load capacity, by defining the nonlinearity level of the system. For values of Φ>10, the results obtained with the modified Reynolds equation with quadratic Forchheimer assumption tend to those obtained with the linear Darcy model, thus showing that this is a more robust and global approach of the problem, and can be used for both pressure-flow assumptions (linear and quadratic). The threshold between linear and quadratic assumptions is numerically investigated for a bronze sintered porous bearing, and the effects of bearing geometry are discussed. Numerical results show that Φ strongly affects the bearing loading capacity and stiffness coefficients. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468072 [article] Modified Reynolds equation for aerostatic porous radial bearings with quadratic forchheimer pressure-flow assumption [texte imprimé] / Rodrigo Nicoletti, Auteur ; Zilda C. Silveira, Auteur ; Benedito M. Purquerio, Auteur . - 2008 . - 12 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 130 n°3 (Juillet 2008) . - 12 p. Mots-clés : Pressure  Flow  (Dynamics)  Porous  materials  Bearings  Equations  Stress  Stiffness Résumé : Aerostatic porous bearings are becoming important elements in precision machines due to their inherent characteristics. The mathematical modeling of such bearings depends on the pressure-flow assumptions that are adopted for the flow in the porous medium. In this work, one proposes a nondimensional modified Reynolds equations based on the quadratic Forchheimer assumption. In this quadratic approach, the nondimensional parameter Φ strongly affects the bearing load capacity, by defining the nonlinearity level of the system. For values of Φ>10, the results obtained with the modified Reynolds equation with quadratic Forchheimer assumption tend to those obtained with the linear Darcy model, thus showing that this is a more robust and global approach of the problem, and can be used for both pressure-flow assumptions (linear and quadratic). The threshold between linear and quadratic assumptions is numerically investigated for a bronze sintered porous bearing, and the effects of bearing geometry are discussed. Numerical results show that Φ strongly affects the bearing loading capacity and stiffness coefficients. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468072