Documents disponibles écrits par cet auteur

Restrictions on the validity of the thermal conditions at the porous-fluid interface / Kun Yang in Journal of heat transfer, Vol. 133 N° 11 (Novembre 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 11 (Novembre 2011) . - pp. [112601/1-12] Titre : Restrictions on the validity of the thermal conditions at the porous-fluid interface : an exact solution Type de document : texte imprimé Auteurs : Kun Yang, Auteur ; Kambiz Vafai, Auteur Année de publication : 2012 Article en page(s) : pp. [112601/1-12] Note générale : Physique Langues : Anglais (eng) Mots-clés : Thermal  condition  Porous-fluis  interface  Local  thermal  nonequilibrium Index. décimale : 536 Chaleur. Thermodynamique Résumé : Thermal conditions at the porous-fluid interface under local thermal nonequilibrium (LTNE) conditions are analyzed in this work. Exact solutions are derived for both the fluid and solid temperature distributions for five of the most fundamental forms of thermal conditions at the interface between a porous medium and a fluid under LTNE conditions and the relationships between these solutions are discussed. This work concentrates on restrictions, based on the physical attributes of the system, which must be placed for validity of the thermal interface conditions. The analytical results clearly point out the range of validity for each model for the first time in the literature. Furthermore, the range of validity of the local thermal equilibrium (LTE) condition is discussed based on the introduction of a critical parameter. The Nusselt number for the fluid at the wall of a channel that contains the fluid and porous medium is also obtained. The effects of the pertinent parameters such as Darcy number, Biot number, Bi, Interface Biot number, Biint, and fluid to solid thermal conductivity ratio are discussed. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000133000011 [...] [article] Restrictions on the validity of the thermal conditions at the porous-fluid interface : an exact solution [texte imprimé] / Kun Yang, Auteur ; Kambiz Vafai, Auteur . - 2012 . - pp. [112601/1-12]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 11 (Novembre 2011) . - pp. [112601/1-12] Mots-clés : Thermal  condition  Porous-fluis  interface  Local  thermal  nonequilibrium Index. décimale : 536 Chaleur. Thermodynamique Résumé : Thermal conditions at the porous-fluid interface under local thermal nonequilibrium (LTNE) conditions are analyzed in this work. Exact solutions are derived for both the fluid and solid temperature distributions for five of the most fundamental forms of thermal conditions at the interface between a porous medium and a fluid under LTNE conditions and the relationships between these solutions are discussed. This work concentrates on restrictions, based on the physical attributes of the system, which must be placed for validity of the thermal interface conditions. The analytical results clearly point out the range of validity for each model for the first time in the literature. Furthermore, the range of validity of the local thermal equilibrium (LTE) condition is discussed based on the introduction of a critical parameter. The Nusselt number for the fluid at the wall of a channel that contains the fluid and porous medium is also obtained. The effects of the pertinent parameters such as Darcy number, Biot number, Bi, Interface Biot number, Biint, and fluid to solid thermal conductivity ratio are discussed. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000133000011 [...]

Transient aspects of heat flux bifurcation in porous media / Kun Yang 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. [052602/1-12] Titre : Transient aspects of heat flux bifurcation in porous media : an exact solution Type de document : texte imprimé Auteurs : Kun Yang, Auteur ; Kambiz Vafai, Auteur Année de publication : 2011 Article en page(s) : pp. [052602/1-12] Note générale : Physique Langues : Anglais (eng) Mots-clés : Porous  media  Heat  flux  bifurcation  Transeint  heat  transfer  Local  thermal  nonequilibrium  Analytical  solution Index. décimale : 536 Chaleur. Thermodynamique Résumé : The transient thermal response of a packed bed is investigated analytically. A local thermal nonequilibrium model is used to represent the energy transport within the porous medium. The heat flux bifurcation phenomenon in porous media is investigated for temporal conditions and two primary types of heat flux bifurcations in porous media are established. Exact solutions are derived for both the fluid and solid temperature distributions for the constant temperature boundary condition. The fluid, solid, and total Nusselt numbers during transient process are analyzed. A heat exchange ratio is introduced to estimate the influence of interactions between the solid and fluid phases through thermal conduction at the wall within the heat flux bifurcation region. A region where the heat transfer can be described without considering the convection contribution in the fluid phase is found. The two-dimensional thermal behavior for the solid and fluid phases is also analyzed. The temporal temperature differential between the solid and fluid is investigated to determine the domain over which the local thermal equilibrium model is valid. In addition, the characteristic time for reaching steady state conditions is evaluated. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Transient aspects of heat flux bifurcation in porous media : an exact solution [texte imprimé] / Kun Yang, Auteur ; Kambiz Vafai, Auteur . - 2011 . - pp. [052602/1-12]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 5 (Mai 2011) . - pp. [052602/1-12] Mots-clés : Porous  media  Heat  flux  bifurcation  Transeint  heat  transfer  Local  thermal  nonequilibrium  Analytical  solution Index. décimale : 536 Chaleur. Thermodynamique Résumé : The transient thermal response of a packed bed is investigated analytically. A local thermal nonequilibrium model is used to represent the energy transport within the porous medium. The heat flux bifurcation phenomenon in porous media is investigated for temporal conditions and two primary types of heat flux bifurcations in porous media are established. Exact solutions are derived for both the fluid and solid temperature distributions for the constant temperature boundary condition. The fluid, solid, and total Nusselt numbers during transient process are analyzed. A heat exchange ratio is introduced to estimate the influence of interactions between the solid and fluid phases through thermal conduction at the wall within the heat flux bifurcation region. A region where the heat transfer can be described without considering the convection contribution in the fluid phase is found. The two-dimensional thermal behavior for the solid and fluid phases is also analyzed. The temporal temperature differential between the solid and fluid is investigated to determine the domain over which the local thermal equilibrium model is valid. In addition, the characteristic time for reaching steady state conditions is evaluated. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]