Documents disponibles écrits par cet auteur

Bejan's constructal theory analysis of gas-liquid cooled finned modules / Giulio Lorenzini in Journal of heat transfer, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 7 (Juillet 2011) . - pp. [071801/1-10] Titre : Bejan's constructal theory analysis of gas-liquid cooled finned modules Type de document : texte imprimé Auteurs : Giulio Lorenzini, Auteur ; Simone Moretti, Auteur Année de publication : 2011 Article en page(s) : pp. [071801/1-10] Note générale : Physique Langues : Anglais (eng) Mots-clés : Benjan's  constructal  theory  Comsol  multiphysics  Heat  removal  Fins  Overall  erformance  coefficient Index. décimale : 536 Chaleur. Thermodynamique Résumé : High performance heat exchangers represent nowadays the key of success to go on with the trend of miniaturizing electronic components as requested by the industry. This numerical study, based on Bejan's Constructal theory, analyzes the thermal behavior of heat removing fin modules, comparing their performances when operating with different types of fluids. In particular, the simulations involve air and water (as representative of gases and liquids), to understand the actual benefits of employing a less heat conductive fluid involving smaller pressure losses or vice versa. The analysis parameters typical of a Constructal description (such as conductance or Overall Performance Coefficient) show that significantly improved performances may be achieved when using water, even if an unavoidable increase in pressure losses affects the liquid-refrigerated case. Considering the overall performance: if the parameter called Relevance tends to 0, air prevails; if it tends to 1, water prevails; if its value is about 0.5, water prevails in most of the case studies. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013300 [...] [article] Bejan's constructal theory analysis of gas-liquid cooled finned modules [texte imprimé] / Giulio Lorenzini, Auteur ; Simone Moretti, Auteur . - 2011 . - pp. [071801/1-10]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 7 (Juillet 2011) . - pp. [071801/1-10] Mots-clés : Benjan's  constructal  theory  Comsol  multiphysics  Heat  removal  Fins  Overall  erformance  coefficient Index. décimale : 536 Chaleur. Thermodynamique Résumé : High performance heat exchangers represent nowadays the key of success to go on with the trend of miniaturizing electronic components as requested by the industry. This numerical study, based on Bejan's Constructal theory, analyzes the thermal behavior of heat removing fin modules, comparing their performances when operating with different types of fluids. In particular, the simulations involve air and water (as representative of gases and liquids), to understand the actual benefits of employing a less heat conductive fluid involving smaller pressure losses or vice versa. The analysis parameters typical of a Constructal description (such as conductance or Overall Performance Coefficient) show that significantly improved performances may be achieved when using water, even if an unavoidable increase in pressure losses affects the liquid-refrigerated case. Considering the overall performance: if the parameter called Relevance tends to 0, air prevails; if it tends to 1, water prevails; if its value is about 0.5, water prevails in most of the case studies. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013300 [...]

Constructal design of cavities inserted into a cylindrical solid body / Giulio Lorenzini in Journal of heat transfer, Vol. 134 N° 7 (Juillet 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 7 (Juillet 2012) . - 06 p. Titre : Constructal design of cavities inserted into a cylindrical solid body Type de document : texte imprimé Auteurs : Giulio Lorenzini, Auteur ; Luiz Alberto Oliveira Rocha, Auteur ; Cesare Biserni, Auteur Année de publication : 2012 Article en page(s) : 06 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : constructal  design;  heat  generating;  cylindical  solid  body Index. décimale : 536 Chaleur. Thermodynamique Résumé : This paper considers the numerical optimization of the shape of cavities that intrude into a cylindrical solid body. The objective is to minimize the global thermal resistance between the solid body and the cavities. Internal heat generating is distributed uniformly throughout the solid body. The cavities are isothermal, while the solid body has adiabatic conditions on the outer surface. The total volume is fixed. The cavities are rectangular, with fixed volume and variable aspect ratio. The number of cavities of the conducting body, N, is a design parameter. The optimized geometry and performance are reported graphically as functions of the ratio between the volume of the cavities and the total volume, phi0, and N. The paper shows an example of the application of optimal distribution of imperfections principle. The results indicate that the optimal distribution of the hot spots is affected not only by the complexity of the configuration (larger N) but also by the area of cavities fraction phi0. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000007 [...] [article] Constructal design of cavities inserted into a cylindrical solid body [texte imprimé] / Giulio Lorenzini, Auteur ; Luiz Alberto Oliveira Rocha, Auteur ; Cesare Biserni, Auteur . - 2012 . - 06 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 7 (Juillet 2012) . - 06 p. Mots-clés : constructal  design;  heat  generating;  cylindical  solid  body Index. décimale : 536 Chaleur. Thermodynamique Résumé : This paper considers the numerical optimization of the shape of cavities that intrude into a cylindrical solid body. The objective is to minimize the global thermal resistance between the solid body and the cavities. Internal heat generating is distributed uniformly throughout the solid body. The cavities are isothermal, while the solid body has adiabatic conditions on the outer surface. The total volume is fixed. The cavities are rectangular, with fixed volume and variable aspect ratio. The number of cavities of the conducting body, N, is a design parameter. The optimized geometry and performance are reported graphically as functions of the ratio between the volume of the cavities and the total volume, phi0, and N. The paper shows an example of the application of optimal distribution of imperfections principle. The results indicate that the optimal distribution of the hot spots is affected not only by the complexity of the configuration (larger N) but also by the area of cavities fraction phi0. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000007 [...]

Constructal design of complex assembly of fins / Giulio Lorenzini in Journal of heat transfer, Vol. 133 N° 8 (Août 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 8 (Août 2011) . - pp. [081902/1-7] Titre : Constructal design of complex assembly of fins Type de document : texte imprimé Auteurs : Giulio Lorenzini, Auteur ; Roberta Lima Correa, Auteur ; Luiz Alberto Oliveira Rocha, Auteur Année de publication : 2011 Article en page(s) : pp. [081902/1-7] Note générale : Physique Langues : Anglais (eng) Mots-clés : Constructal  design  Enhanced  heat  transfer  Fins  Optimization Index. décimale : 536 Chaleur. Thermodynamique Résumé : Constructal design is a method that conducts the designer toward flow (e.g., heat flux) architectures that have greater global performance. This numerical work uses this method to seek for the best geometry of a complex assembly of fins, i.e., an assembly where there is a cavity between the two branches of the T-Y-assembly of fins and two additional extended surfaces. The global thermal resistance of the assembly is minimized four times by geometric optimization subject to the following constraints: the total volume, the volume of fin material, the volume of the cavity, and the volume of the two additional extended surfaces. Larger amount of fin material improves the performance of the assembly of fins. The three times optimized global thermal resistance of the complex assembly of fins performs 32% better than the best T-Y-configuration under the same thermal and geometric conditions. The three times minimized global thermal resistance of the complex assembly of fins was correlated by power laws as a function of its corresponding optimal configurations. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013300 [...] [article] Constructal design of complex assembly of fins [texte imprimé] / Giulio Lorenzini, Auteur ; Roberta Lima Correa, Auteur ; Luiz Alberto Oliveira Rocha, Auteur . - 2011 . - pp. [081902/1-7]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 8 (Août 2011) . - pp. [081902/1-7] Mots-clés : Constructal  design  Enhanced  heat  transfer  Fins  Optimization Index. décimale : 536 Chaleur. Thermodynamique Résumé : Constructal design is a method that conducts the designer toward flow (e.g., heat flux) architectures that have greater global performance. This numerical work uses this method to seek for the best geometry of a complex assembly of fins, i.e., an assembly where there is a cavity between the two branches of the T-Y-assembly of fins and two additional extended surfaces. The global thermal resistance of the assembly is minimized four times by geometric optimization subject to the following constraints: the total volume, the volume of fin material, the volume of the cavity, and the volume of the two additional extended surfaces. Larger amount of fin material improves the performance of the assembly of fins. The three times optimized global thermal resistance of the complex assembly of fins performs 32% better than the best T-Y-configuration under the same thermal and geometric conditions. The three times minimized global thermal resistance of the complex assembly of fins was correlated by power laws as a function of its corresponding optimal configurations. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013300 [...]