Documents disponibles écrits par cet auteur

Confocal microscopy for capillary film measurements in a flat plate heat pipe / Frédéric Lefèvre in Journal of heat transfer, Vol. 132 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 3 (Mars 2010) . - pp. [031502-1/6] Titre : Confocal microscopy for capillary film measurements in a flat plate heat pipe Type de document : texte imprimé Auteurs : Frédéric Lefèvre, Auteur ; Romuald Rullière, Auteur ; Stéphane Lips, Auteur Article en page(s) : pp. [031502-1/6] Note générale : Physique Langues : Anglais (eng) Mots-clés : Evaporation  Condensation  Flat  plate  heat  pipes  Thin  film  Capillarity Index. décimale : 536 Chaleur. Thermodynamique Résumé : This paper aims to show how confocal microscopy can be useful for characterizing menisci in a flat plate heat pipe made of silicon. The capillary structure is made of radial microgrooves whose width decreases from the periphery to the center of the system. A transparent plate is used to close the system and allow visualizations. The confocal method allows measuring both the liquid film shape inside the grooves and the condensate films on the fins. The film thickness is lower than 10 µm. The measurements show that the condensate film forms a drop connected to the meniscus in the grooves but their curvatures are reversed. As a result, a very thin region shall exist where the liquid formed by condensation is drained to the grooves. The drop curvature radius decreases from the condenser to the evaporator like the meniscus radius in the grooves. Therefore, a small part of the liquid is drained by the fins from the evaporator to the condenser. Furthermore, the condensate film covers a large part of the system and can also be in contact with the evaporator at high heat fluxes. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Confocal microscopy for capillary film measurements in a flat plate heat pipe [texte imprimé] / Frédéric Lefèvre, Auteur ; Romuald Rullière, Auteur ; Stéphane Lips, Auteur . - pp. [031502-1/6]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 3 (Mars 2010) . - pp. [031502-1/6] Mots-clés : Evaporation  Condensation  Flat  plate  heat  pipes  Thin  film  Capillarity Index. décimale : 536 Chaleur. Thermodynamique Résumé : This paper aims to show how confocal microscopy can be useful for characterizing menisci in a flat plate heat pipe made of silicon. The capillary structure is made of radial microgrooves whose width decreases from the periphery to the center of the system. A transparent plate is used to close the system and allow visualizations. The confocal method allows measuring both the liquid film shape inside the grooves and the condensate films on the fins. The film thickness is lower than 10 µm. The measurements show that the condensate film forms a drop connected to the meniscus in the grooves but their curvatures are reversed. As a result, a very thin region shall exist where the liquid formed by condensation is drained to the grooves. The drop curvature radius decreases from the condenser to the evaporator like the meniscus radius in the grooves. Therefore, a small part of the liquid is drained by the fins from the evaporator to the condenser. Furthermore, the condensate film covers a large part of the system and can also be in contact with the evaporator at high heat fluxes. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Thermohydraulic study of a flat plate heat pipe by means of confocal microscopy / Stéphane Lips in Journal of heat transfer, Vol. 132 N° 11 (Novembre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 11 (Novembre 2010) . - pp. [112901-1/9] Titre : Thermohydraulic study of a flat plate heat pipe by means of confocal microscopy : application to a 2D capillary structure Type de document : texte imprimé Auteurs : Stéphane Lips, Auteur ; Frédéric Lefèvre, Auteur ; Bonjour, Jocelyn, Auteur Année de publication : 2010 Article en page(s) : pp. [112901-1/9] Note générale : Physique Langues : Anglais (eng) Mots-clés : Flat  plate  heat  pipe  Crossed  grooves  2D  capillary  structure  Confocal  microscopy  Meniscus Index. décimale : 536 Chaleur. Thermodynamique Résumé : Thermal and hydrodynamic experimental results of a flat plate heat pipe (FPHP) are presented. The capillary structure is made of crossed grooves machined in a copper plate. The shape of the liquid-vapor interface in this type of capillary structure—that can also be viewed as an array of posts—is studied theoretically and experimentally. A confocal microscope is used to visualize the liquid-vapor interface and thus the capillary pressure field in the system. These hydrodynamic measurements, coupled to temperature measurements on the FPHP wall, are used to estimate the permeability and the equivalent thermal conductivity of the capillary structure filled with methanol or FC72. These parameters are obtained from a comparison between the experimental data and an analytical model. Finally, the model is used to compare the draining capability of crossed grooves with that of longitudinal grooves. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Thermohydraulic study of a flat plate heat pipe by means of confocal microscopy : application to a 2D capillary structure [texte imprimé] / Stéphane Lips, Auteur ; Frédéric Lefèvre, Auteur ; Bonjour, Jocelyn, Auteur . - 2010 . - pp. [112901-1/9]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 11 (Novembre 2010) . - pp. [112901-1/9] Mots-clés : Flat  plate  heat  pipe  Crossed  grooves  2D  capillary  structure  Confocal  microscopy  Meniscus Index. décimale : 536 Chaleur. Thermodynamique Résumé : Thermal and hydrodynamic experimental results of a flat plate heat pipe (FPHP) are presented. The capillary structure is made of crossed grooves machined in a copper plate. The shape of the liquid-vapor interface in this type of capillary structure—that can also be viewed as an array of posts—is studied theoretically and experimentally. A confocal microscope is used to visualize the liquid-vapor interface and thus the capillary pressure field in the system. These hydrodynamic measurements, coupled to temperature measurements on the FPHP wall, are used to estimate the permeability and the equivalent thermal conductivity of the capillary structure filled with methanol or FC72. These parameters are obtained from a comparison between the experimental data and an analytical model. Finally, the model is used to compare the draining capability of crossed grooves with that of longitudinal grooves. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]