Documents disponibles écrits par cet auteur

Evaluation of compact and effective air-cooled carbon foam heat sink / W. Wu 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. [054504/1-5] Titre : Evaluation of compact and effective air-cooled carbon foam heat sink Type de document : texte imprimé Auteurs : W. Wu, Auteur ; J. H. Du, Auteur ; Y. R. Lin, Auteur Année de publication : 2011 Article en page(s) : pp. [054504/1-5] Note générale : Physique Langues : Anglais (eng) Mots-clés : Carbon  foam  Thermal  management  Electronics  cooling Index. décimale : 536 Chaleur. Thermodynamique Résumé : This study investigates a V-shaped corrugated carbon foam heat sink for thermal management of electronics with forced air convection. Experiments were conducted to determine the heat sink performance in terms of heat transfer coefficient and pressure drop. The test section, with overall dimensions of 51 mm L×51 mm W×19 mm H, enabled up to 166 W of heat dissipation, and 3280 W/m2 K and 2210 W/m2 K heat transfer coefficients, based on log mean and air inlet temperatures, respectively, at 7.8 m/s air flow speed, and 1320 Pa pressure loss. Compared to a solid carbon foam, the V-shaped corrugated structure enhances the heat transfer, and at the same time reduces the flow resistance. Physical mechanisms underlying the observed phenomena are briefly explained. With benefits that potentially can reduce overall weight, volume, and cost of the air-cooled electronics, the present V-shaped corrugated carbon foam emerges as an alternative heat sink. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Evaluation of compact and effective air-cooled carbon foam heat sink [texte imprimé] / W. Wu, Auteur ; J. H. Du, Auteur ; Y. R. Lin, Auteur . - 2011 . - pp. [054504/1-5]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 5 (Mai 2011) . - pp. [054504/1-5] Mots-clés : Carbon  foam  Thermal  management  Electronics  cooling Index. décimale : 536 Chaleur. Thermodynamique Résumé : This study investigates a V-shaped corrugated carbon foam heat sink for thermal management of electronics with forced air convection. Experiments were conducted to determine the heat sink performance in terms of heat transfer coefficient and pressure drop. The test section, with overall dimensions of 51 mm L×51 mm W×19 mm H, enabled up to 166 W of heat dissipation, and 3280 W/m2 K and 2210 W/m2 K heat transfer coefficients, based on log mean and air inlet temperatures, respectively, at 7.8 m/s air flow speed, and 1320 Pa pressure loss. Compared to a solid carbon foam, the V-shaped corrugated structure enhances the heat transfer, and at the same time reduces the flow resistance. Physical mechanisms underlying the observed phenomena are briefly explained. With benefits that potentially can reduce overall weight, volume, and cost of the air-cooled electronics, the present V-shaped corrugated carbon foam emerges as an alternative heat sink. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Experimental study on heat transfer and pressure drop of recuperative heat exchangers using carbon foam / Y. R. Lin in Journal of heat transfer, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 9 (Septembre 2010) . - pp. [091902-1/10] Titre : Experimental study on heat transfer and pressure drop of recuperative heat exchangers using carbon foam Type de document : texte imprimé Auteurs : Y. R. Lin, Auteur ; J. H. Du, Auteur ; W. Wu, Auteur Article en page(s) : pp. [091902-1/10] Note générale : Physique Langues : Anglais (eng) Mots-clés : Heat  transfer  Recuperators  Cryogenics Index. décimale : 536 Chaleur. Thermodynamique Résumé : This work focuses on the development of high-effectiveness recuperative heat exchangers using solid and corrugated carbon foam blocks. Characterization tests were conducted on heat transfer and pressure drop for a single carbon foam block with different sizes. Results show that carbon foam can be an effective medium for heat transfer enhancement, and a short length in the flow direction yields a high heat transfer coefficient. The corrugation can enhance heat transfer and reduce pressure drop at the same time. A recuperative heat exchanger with carbon foam, which consists of separate blocks of carbon foams packed between thin sheets of stainless steel, was designed. The hot and cold flow paths were arranged in counterflow in the recuperator. The heat exchanger was designed in a modular manner so that it can be scaled up for a larger heat transfer requirement or a higher overall effectiveness. The anisotropic property of carbon foam was exploited to achieve higher effectiveness for one pair of foam blocks. Experiments with four pairs of carbon foams were conducted to evaluate the performance of carbon foam used in the recuperative heat exchanger. Measurements were made for both solid and corrugated foams for comparison. With four pairs of carbon foam blocks, an overall effectiveness epsilontotal greater than 80% was achieved. This paper demonstrates an approach to reach an effectiveness epsilontotal of 98% by placing many pairs of carbon foams in series. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Experimental study on heat transfer and pressure drop of recuperative heat exchangers using carbon foam [texte imprimé] / Y. R. Lin, Auteur ; J. H. Du, Auteur ; W. Wu, Auteur . - pp. [091902-1/10]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 9 (Septembre 2010) . - pp. [091902-1/10] Mots-clés : Heat  transfer  Recuperators  Cryogenics Index. décimale : 536 Chaleur. Thermodynamique Résumé : This work focuses on the development of high-effectiveness recuperative heat exchangers using solid and corrugated carbon foam blocks. Characterization tests were conducted on heat transfer and pressure drop for a single carbon foam block with different sizes. Results show that carbon foam can be an effective medium for heat transfer enhancement, and a short length in the flow direction yields a high heat transfer coefficient. The corrugation can enhance heat transfer and reduce pressure drop at the same time. A recuperative heat exchanger with carbon foam, which consists of separate blocks of carbon foams packed between thin sheets of stainless steel, was designed. The hot and cold flow paths were arranged in counterflow in the recuperator. The heat exchanger was designed in a modular manner so that it can be scaled up for a larger heat transfer requirement or a higher overall effectiveness. The anisotropic property of carbon foam was exploited to achieve higher effectiveness for one pair of foam blocks. Experiments with four pairs of carbon foams were conducted to evaluate the performance of carbon foam used in the recuperative heat exchanger. Measurements were made for both solid and corrugated foams for comparison. With four pairs of carbon foam blocks, an overall effectiveness epsilontotal greater than 80% was achieved. This paper demonstrates an approach to reach an effectiveness epsilontotal of 98% by placing many pairs of carbon foams in series. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Feasible input manipulation for a nonisothermal direct methanol fuel cell system / W. Wu in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5725–5733 Titre : Feasible input manipulation for a nonisothermal direct methanol fuel cell system Type de document : texte imprimé Auteurs : W. Wu, Auteur ; Y.-T. Lin, Auteur Année de publication : 2010 Article en page(s) : pp. 5725–5733 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Direct  methanol  fuel  cell  Methanol  crossover  Water  crossover Résumé : Through a semiexperimental dynamic modeling of a direct methanol fuel cell (DMFC) system, transient behaviors on describing cell temperature, methanol crossover, water crossover, and electric power are presented. By different operating manners, the new input determinations are addressed. To investigate the performance of DMFC systems, the presented fuel and exergetic efficiencies for the specific probe of energy utilization are evaluated. Through both steady-state and unsteady state analyses, the manipulation of cathode pressure and anode inlet flow temperature is a feasible approach for temperature regulation, but methanol crossover is restricted. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901829a [article] Feasible input manipulation for a nonisothermal direct methanol fuel cell system [texte imprimé] / W. Wu, Auteur ; Y.-T. Lin, Auteur . - 2010 . - pp. 5725–5733. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5725–5733 Mots-clés : Direct  methanol  fuel  cell  Methanol  crossover  Water  crossover Résumé : Through a semiexperimental dynamic modeling of a direct methanol fuel cell (DMFC) system, transient behaviors on describing cell temperature, methanol crossover, water crossover, and electric power are presented. By different operating manners, the new input determinations are addressed. To investigate the performance of DMFC systems, the presented fuel and exergetic efficiencies for the specific probe of energy utilization are evaluated. Through both steady-state and unsteady state analyses, the manipulation of cathode pressure and anode inlet flow temperature is a feasible approach for temperature regulation, but methanol crossover is restricted. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901829a

Model tests on discontinuities in subsurface barrier installed by the vibrating beam method / W. Wu in Journal of geotechnical and geoenvironmental engineering, Vol. 134 N°4 (Avril 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N°4 (Avril 2008) . - pp. 541–546 Titre : Model tests on discontinuities in subsurface barrier installed by the vibrating beam method Type de document : texte imprimé Auteurs : W. Wu, Auteur ; F. Aschauer, Auteur ; G. Reiser, Auteur Année de publication : 2008 Article en page(s) : pp. 541–546 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Fine-grained  soil  Model  tests  Barriers  Clays  Silts  Groundwater  pollution Résumé : In the present note, the susceptibility to necking of a subsurface barrier installed by the vibrating beam method in fine-grained soils is investigated by physical model tests. Two soils are investigated, a clayey soil and a silty soil. The model soil is prepared by moist tamping. The recipe of slurry in the model tests is widely used in the foundation engineering industry. The dynamic loading exerted by the vibration of the adjacent panel is simulated by a shake table. The test results show that soil plasticity and water content are the major influence factors on the susceptibility to necking. The plasticity index can be used as an indicator for the susceptibility to necking of subsurface barrier installed by the vibrating beam method in fine-grained soils. Other influence factors on necking are also investigated and their implications for practice are discussed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A4%2854 [...] [article] Model tests on discontinuities in subsurface barrier installed by the vibrating beam method [texte imprimé] / W. Wu, Auteur ; F. Aschauer, Auteur ; G. Reiser, Auteur . - 2008 . - pp. 541–546. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N°4 (Avril 2008) . - pp. 541–546 Mots-clés : Fine-grained  soil  Model  tests  Barriers  Clays  Silts  Groundwater  pollution Résumé : In the present note, the susceptibility to necking of a subsurface barrier installed by the vibrating beam method in fine-grained soils is investigated by physical model tests. Two soils are investigated, a clayey soil and a silty soil. The model soil is prepared by moist tamping. The recipe of slurry in the model tests is widely used in the foundation engineering industry. The dynamic loading exerted by the vibration of the adjacent panel is simulated by a shake table. The test results show that soil plasticity and water content are the major influence factors on the susceptibility to necking. The plasticity index can be used as an indicator for the susceptibility to necking of subsurface barrier installed by the vibrating beam method in fine-grained soils. Other influence factors on necking are also investigated and their implications for practice are discussed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A4%2854 [...]

Numerical model of electro-osmotic consolidation in clay / L. Hu in Géotechnique, Vol. 62 N° 6 (Juin 2012) 

Public ISBD [article]  in Géotechnique > Vol. 62 N° 6 (Juin 2012) . - pp. 537 –541 Titre : Numerical model of electro-osmotic consolidation in clay Type de document : texte imprimé Auteurs : L. Hu, Auteur ; W. Wu, Auteur ; H. Wu, Auteur Année de publication : 2012 Article en page(s) : pp. 537 –541 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Numerical  modelling  Electrokinetics  Consolidation  Pore  pressures Résumé : Electro-osmotic consolidation is a unique soil improvement technique. A physics-based model for electro-osmotic consolidation is proposed, in which Biot's consolidation equation is coupled with the electro-osmotic flow and control equation for an electrical field, and the displacement of soil mass and pore-water pressure can be obtained. Furthermore, the non-linear variation of the mechanical and electrical properties of the soil mass during consolidation is incorporated into the model. The numerical solution agrees well with the analytical solution. The developed model can predict the ground displacement and provide useful data for the design of an electro-osmosis treatment system. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.11.T.008 [article] Numerical model of electro-osmotic consolidation in clay [texte imprimé] / L. Hu, Auteur ; W. Wu, Auteur ; H. Wu, Auteur . - 2012 . - pp. 537 –541. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 62 N° 6 (Juin 2012) . - pp. 537 –541 Mots-clés : Numerical  modelling  Electrokinetics  Consolidation  Pore  pressures Résumé : Electro-osmotic consolidation is a unique soil improvement technique. A physics-based model for electro-osmotic consolidation is proposed, in which Biot's consolidation equation is coupled with the electro-osmotic flow and control equation for an electrical field, and the displacement of soil mass and pore-water pressure can be obtained. Furthermore, the non-linear variation of the mechanical and electrical properties of the soil mass during consolidation is incorporated into the model. The numerical solution agrees well with the analytical solution. The developed model can predict the ground displacement and provide useful data for the design of an electro-osmosis treatment system. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.11.T.008