Documents disponibles écrits par cet auteur

On the generalized Brinkman number definition and its importance for Bingham fluids / P. M. Coelho in Journal of heat transfer, Vol. 133 N° 5 (Mai 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 5 (Mai 2011) . - pp. [054505/1-4] Titre : On the generalized Brinkman number definition and its importance for Bingham fluids Type de document : texte imprimé Auteurs : P. M. Coelho, Auteur ; J. C. Faria, Auteur Année de publication : 2011 Article en page(s) : pp. [054505/1-4] Note générale : Physique Langues : Anglais (eng) Mots-clés : Bingham  fluid  Viscous  dissipation  Convective  heat  transfer  Generalized  Brinkman  number  Duct  flows Index. décimale : 536 Chaleur. Thermodynamique Résumé : In this technical note we discuss the importance of using a generalized Brinkman number definition for laminar pipe flow of a Bingham fluid, when viscous dissipation effects are relevant. We show that adapting the Brinkman number definition commonly used for Newtonian fluids directly to the more general class of non-Newtonian fluids does not calculate correctly the ratio between heat generated by viscous dissipation and heat transfer at the wall and leads to a distortion of the graphical representation of the Nusselt number, Nu, rendering difficult, if not impossible, the comparisons of the Nu behavior between different Brinkman numbers. The use of the proposed generalized Brinkman number removes these problems and simultaneously it has the merit of being independent of any reference apparent viscosities. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] On the generalized Brinkman number definition and its importance for Bingham fluids [texte imprimé] / P. M. Coelho, Auteur ; J. C. Faria, Auteur . - 2011 . - pp. [054505/1-4]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 5 (Mai 2011) . - pp. [054505/1-4] Mots-clés : Bingham  fluid  Viscous  dissipation  Convective  heat  transfer  Generalized  Brinkman  number  Duct  flows Index. décimale : 536 Chaleur. Thermodynamique Résumé : In this technical note we discuss the importance of using a generalized Brinkman number definition for laminar pipe flow of a Bingham fluid, when viscous dissipation effects are relevant. We show that adapting the Brinkman number definition commonly used for Newtonian fluids directly to the more general class of non-Newtonian fluids does not calculate correctly the ratio between heat generated by viscous dissipation and heat transfer at the wall and leads to a distortion of the graphical representation of the Nusselt number, Nu, rendering difficult, if not impossible, the comparisons of the Nu behavior between different Brinkman numbers. The use of the proposed generalized Brinkman number removes these problems and simultaneously it has the merit of being independent of any reference apparent viscosities. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

A simplified method for calculating heat transfer coefficients and friction factors in laminar pipe flow of non-Newtonian fluids / D. A. Cruz in Journal of heat transfer, Vol 134 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol 134 N° 9 (Septembre 2012) . - 06 p. Titre : A simplified method for calculating heat transfer coefficients and friction factors in laminar pipe flow of non-Newtonian fluids Type de document : texte imprimé Auteurs : D. A. Cruz, Auteur ; P. M. Coelho, Auteur ; M. A. Alves, Auteur Année de publication : 2012 Article en page(s) : 06 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : approximate  method;  Nusselt  number;  heat  transfer;  fully  developed  pipe  flow;  laminar  flow;  generalized  Newtonian  fluid;  friction  factor Index. décimale : 536 Chaleur. Thermodynamique Résumé : In this work, we propose an approximate methodology to estimate the Nusselt number and friction factor in fully developed non-Newtonian laminar flow in circular pipes for a constant wall heat flux. The methodology was tested using several constitutive equations, including generalized Newtonian fluids and viscoelastic models such as the simplified Phan-Thien–Tanner (sPTT), Herschel–Bulkley, Bingham, Casson, and Carreau–Yasuda constitutive equations. The error of the approximate methodology was found to be smaller than 3.2%, except for the fluids with yield stress for which the maximum error increased to about 8% for the cases analyzed, which cover a wide range of shear viscosity curves. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000009 [...] [article] A simplified method for calculating heat transfer coefficients and friction factors in laminar pipe flow of non-Newtonian fluids [texte imprimé] / D. A. Cruz, Auteur ; P. M. Coelho, Auteur ; M. A. Alves, Auteur . - 2012 . - 06 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol 134 N° 9 (Septembre 2012) . - 06 p. Mots-clés : approximate  method;  Nusselt  number;  heat  transfer;  fully  developed  pipe  flow;  laminar  flow;  generalized  Newtonian  fluid;  friction  factor Index. décimale : 536 Chaleur. Thermodynamique Résumé : In this work, we propose an approximate methodology to estimate the Nusselt number and friction factor in fully developed non-Newtonian laminar flow in circular pipes for a constant wall heat flux. The methodology was tested using several constitutive equations, including generalized Newtonian fluids and viscoelastic models such as the simplified Phan-Thien–Tanner (sPTT), Herschel–Bulkley, Bingham, Casson, and Carreau–Yasuda constitutive equations. The error of the approximate methodology was found to be smaller than 3.2%, except for the fluids with yield stress for which the maximum error increased to about 8% for the cases analyzed, which cover a wide range of shear viscosity curves. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000009 [...]