Documents disponibles écrits par cet auteur

Entropy generation analysis for nanofluid flow in microchannels / Jie Li in Journal of heat transfer, Vol. 132 N° 12 (Décembre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 12 (Décembre 2010) . - pp. [122401-1/8] Titre : Entropy generation analysis for nanofluid flow in microchannels Type de document : texte imprimé Auteurs : Jie Li, Auteur ; Clement Kleinstreuer, Auteur Année de publication : 2010 Article en page(s) : pp. [122401-1/8] Note générale : Physique Langues : Anglais (eng) Mots-clés : Computer  simulation  Nanofluid  flow  Entropy  minimization  Microchannel  geometry  Microchannel  operation Index. décimale : 536 Chaleur. Thermodynamique Résumé : Employing a validated computer simulation model, entropy generation is analyzed in trapezoidal microchannels for steady laminar flow of pure water and CuO-water nanofluids. Focusing on microchannel heat sink applications, local and volumetric entropy rates caused by frictional and thermal effects are computed for different coolants, inlet temperatures, Reynolds numbers, and channel aspect ratios. It was found that there exists an optimal Reynolds number range to operate the system due to the characteristics of the two different entropy sources, both related to the inlet Reynolds number. Microchannels with high aspect ratios have a lower suitable operational Reynolds number range. The employment of nanofluids can further minimize entropy generation because of their superior thermal properties. Heat transfer induced entropy generation is dominant for typical microheating systems while frictional entropy generation becomes more and more important with the increase in fluid inlet velocity/Reynolds number. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Entropy generation analysis for nanofluid flow in microchannels [texte imprimé] / Jie Li, Auteur ; Clement Kleinstreuer, Auteur . - 2010 . - pp. [122401-1/8]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 12 (Décembre 2010) . - pp. [122401-1/8] Mots-clés : Computer  simulation  Nanofluid  flow  Entropy  minimization  Microchannel  geometry  Microchannel  operation Index. décimale : 536 Chaleur. Thermodynamique Résumé : Employing a validated computer simulation model, entropy generation is analyzed in trapezoidal microchannels for steady laminar flow of pure water and CuO-water nanofluids. Focusing on microchannel heat sink applications, local and volumetric entropy rates caused by frictional and thermal effects are computed for different coolants, inlet temperatures, Reynolds numbers, and channel aspect ratios. It was found that there exists an optimal Reynolds number range to operate the system due to the characteristics of the two different entropy sources, both related to the inlet Reynolds number. Microchannels with high aspect ratios have a lower suitable operational Reynolds number range. The employment of nanofluids can further minimize entropy generation because of their superior thermal properties. Heat transfer induced entropy generation is dominant for typical microheating systems while frictional entropy generation becomes more and more important with the increase in fluid inlet velocity/Reynolds number. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Optimal drug-aerosol delivery to predetermined ung sites / Clement Kleinstreuer in Journal of heat transfer, Vol. 133 N° 1(N° Spécial) (Janvier 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 1(N° Spécial) (Janvier 2011) . - pp. [011002/1-12] Titre : Optimal drug-aerosol delivery to predetermined ung sites Type de document : texte imprimé Auteurs : Clement Kleinstreuer, Auteur ; Zhe Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. [011002/1-12] Note générale : Physique Langues : Anglais (eng) Mots-clés : Subject-specific  lung  airways  Air-particle  flow  Computer  simulation  results  Inhaler  devices  Optimal  drug-aerosol  targeting  Smart  inhaler  system Index. décimale : 536 Chaleur. Thermodynamique Résumé : This review summarizes computer simulation methodologies of air-particle flow, results of drug-aerosol transport/deposition in models of the human respiratory system, as well as aspects of drug-aerosol targeting and associated inhalation devices. After a brief introduction to drug delivery systems in general, the required modeling and simulation steps for optimal drug-aerosol delivery in the lung are outlined. Starting with medical imaging and file conversion of patient-specific lung-airway morphologies, the air-particle transport phenomena are numerically solved for a representative inhalation flow rate of Qtotal=30 l/min. Focusing on microspheres and droplets, the complex airflow and particle dynamics, as well as the droplet heat and mass transfer are illustrated. With this foundation as the background, an overview of present inhaler devices is presented, followed by a discussion of the methodology and features of a new smart inhaler system (SIS). With the SIS, inhaled drug-aerosols can be directly delivered to any predetermined target area in the human lung. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Optimal drug-aerosol delivery to predetermined ung sites [texte imprimé] / Clement Kleinstreuer, Auteur ; Zhe Zhang, Auteur . - 2011 . - pp. [011002/1-12]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 1(N° Spécial) (Janvier 2011) . - pp. [011002/1-12] Mots-clés : Subject-specific  lung  airways  Air-particle  flow  Computer  simulation  results  Inhaler  devices  Optimal  drug-aerosol  targeting  Smart  inhaler  system Index. décimale : 536 Chaleur. Thermodynamique Résumé : This review summarizes computer simulation methodologies of air-particle flow, results of drug-aerosol transport/deposition in models of the human respiratory system, as well as aspects of drug-aerosol targeting and associated inhalation devices. After a brief introduction to drug delivery systems in general, the required modeling and simulation steps for optimal drug-aerosol delivery in the lung are outlined. Starting with medical imaging and file conversion of patient-specific lung-airway morphologies, the air-particle transport phenomena are numerically solved for a representative inhalation flow rate of Qtotal=30 l/min. Focusing on microspheres and droplets, the complex airflow and particle dynamics, as well as the droplet heat and mass transfer are illustrated. With this foundation as the background, an overview of present inhaler devices is presented, followed by a discussion of the methodology and features of a new smart inhaler system (SIS). With the SIS, inhaled drug-aerosols can be directly delivered to any predetermined target area in the human lung. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Thermal nanofluid property model with application to nanofluid flow in a parallel-disk system—part I: a new thermal conductivity model for nanofluid flow / Clement Kleinstreuer in Journal of heat transfer, Vol. 134 N° 5 (Mai 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 5 (Mai 2012) . - 11 p. Titre : Thermal nanofluid property model with application to nanofluid flow in a parallel-disk system—part I: a new thermal conductivity model for nanofluid flow Type de document : texte imprimé Auteurs : Clement Kleinstreuer, Auteur ; Yu Feng, Auteur Année de publication : 2012 Article en page(s) : 11 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : nanofluids;  thermal  conductivity  enhancement;  new  theory;  data  comparisons Index. décimale : 536 Chaleur. Thermodynamique Résumé : This is a two-part paper, which proposes a new theory explaining the experimentally observed enhancement of the thermal conductivity, knf, of nanofluids (Part I) and discusses simulation results of nanofluid flow in a radial parallel-plate channel using different knf-models (Part II). Specifically, Part I provides the derivation of the new model as well as comparisons with benchmark experimental data sets and other theories, focusing mainly on aluminum and copper oxide nanoparticles in water. The new thermal conductivity expression consists of a base-fluid static part, kbf, and a new “micromixing” part, kmm, i.e., knf = kbf + kmm. While kbf relies on Maxwell's theory, kmm encapsulates nanoparticle characteristics and liquid properties as well as Brownian-motion induced nanoparticle fluctuations, nanoparticle volume fractions, mixture-temperature changes, particle–particle interactions, and random temperature fluctuations causing liquid-particle interactions. Thus, fundamental physics principles include the Brownian-motion effect, an extended Langevin equation with scaled interaction forces, and a turbulence-inspired heat transfer equation. The new model predicts experimental data for several types of metal-oxide nanoparticles (20 < dp < 50 nm) in water with volume fractions up to 5% and mixture temperatures below 350 K. While the three competitive theories considered match selectively experimental data, their needs for curve-fitted functions and arbitrary parameters make these models not generally applicable. The new theory can be readily extended to accommodate other types of nanoparticle-liquid pairings and to include nonspherical nanomaterial. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000005 [...] [article] Thermal nanofluid property model with application to nanofluid flow in a parallel-disk system—part I: a new thermal conductivity model for nanofluid flow [texte imprimé] / Clement Kleinstreuer, Auteur ; Yu Feng, Auteur . - 2012 . - 11 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 5 (Mai 2012) . - 11 p. Mots-clés : nanofluids;  thermal  conductivity  enhancement;  new  theory;  data  comparisons Index. décimale : 536 Chaleur. Thermodynamique Résumé : This is a two-part paper, which proposes a new theory explaining the experimentally observed enhancement of the thermal conductivity, knf, of nanofluids (Part I) and discusses simulation results of nanofluid flow in a radial parallel-plate channel using different knf-models (Part II). Specifically, Part I provides the derivation of the new model as well as comparisons with benchmark experimental data sets and other theories, focusing mainly on aluminum and copper oxide nanoparticles in water. The new thermal conductivity expression consists of a base-fluid static part, kbf, and a new “micromixing” part, kmm, i.e., knf = kbf + kmm. While kbf relies on Maxwell's theory, kmm encapsulates nanoparticle characteristics and liquid properties as well as Brownian-motion induced nanoparticle fluctuations, nanoparticle volume fractions, mixture-temperature changes, particle–particle interactions, and random temperature fluctuations causing liquid-particle interactions. Thus, fundamental physics principles include the Brownian-motion effect, an extended Langevin equation with scaled interaction forces, and a turbulence-inspired heat transfer equation. The new model predicts experimental data for several types of metal-oxide nanoparticles (20 < dp < 50 nm) in water with volume fractions up to 5% and mixture temperatures below 350 K. While the three competitive theories considered match selectively experimental data, their needs for curve-fitted functions and arbitrary parameters make these models not generally applicable. The new theory can be readily extended to accommodate other types of nanoparticle-liquid pairings and to include nonspherical nanomaterial. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000005 [...]

Thermal nanofluid property model with application to nanofluid flow in a parallel disk system—part II: nanofluid flow between parallel disks / Yu Feng in Journal of heat transfer, Vol. 134 N° 5 (Mai 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 5 (Mai 2012) . - 09 p. Titre : Thermal nanofluid property model with application to nanofluid flow in a parallel disk system—part II: nanofluid flow between parallel disks Type de document : texte imprimé Auteurs : Yu Feng, Auteur ; Clement Kleinstreuer, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : nanofluid  flow;  augmented  heat  transfer;  parallel  disk  system Index. décimale : 536 Chaleur. Thermodynamique Résumé : This is the second part of a two-part paper which proposes a new theory explaining the experimentally observed enhancement of the thermal conductivity, knf, of nanofluids (Part I) and discusses simulation results of nanofluid flow in an axisymmetric jet-impingement cooling system using different knf-models (Part II). Specifically, Part II provides numerical simulations of convective nanofluid heat transfer in terms of velocity profiles, friction factor, temperature distributions, and Nusselt numbers, employing the new knf-model. Flow structures and the effects of nanoparticle addition on heat transfer and entropy generation are discussed as well. Analytical expressions for velocity profiles and friction factors, assuming quasi-fully-developed flow between parallel disks, have been derived and validated for nanofluids as well. Based on the numerical simulation results for both alumina-water nanofluids and pure water, it can be concluded that nanofluids show better heat transfer performance than convectional coolants with no great penalty in pumping power. Furthermore, the system's entropy generation rate is lower for nanofluids than for pure water. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000005 [...] [article] Thermal nanofluid property model with application to nanofluid flow in a parallel disk system—part II: nanofluid flow between parallel disks [texte imprimé] / Yu Feng, Auteur ; Clement Kleinstreuer, Auteur . - 2012 . - 09 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 5 (Mai 2012) . - 09 p. Mots-clés : nanofluid  flow;  augmented  heat  transfer;  parallel  disk  system Index. décimale : 536 Chaleur. Thermodynamique Résumé : This is the second part of a two-part paper which proposes a new theory explaining the experimentally observed enhancement of the thermal conductivity, knf, of nanofluids (Part I) and discusses simulation results of nanofluid flow in an axisymmetric jet-impingement cooling system using different knf-models (Part II). Specifically, Part II provides numerical simulations of convective nanofluid heat transfer in terms of velocity profiles, friction factor, temperature distributions, and Nusselt numbers, employing the new knf-model. Flow structures and the effects of nanoparticle addition on heat transfer and entropy generation are discussed as well. Analytical expressions for velocity profiles and friction factors, assuming quasi-fully-developed flow between parallel disks, have been derived and validated for nanofluids as well. Based on the numerical simulation results for both alumina-water nanofluids and pure water, it can be concluded that nanofluids show better heat transfer performance than convectional coolants with no great penalty in pumping power. Furthermore, the system's entropy generation rate is lower for nanofluids than for pure water. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000005 [...]