Design and test of carbon nanotube biwick structure for high-heat-flux phase change heat transfer / Qingjun Cai in Journal of heat transfer, Vol. 132 N° 5 (Mai 2010)  

Public ISBD [article]  inJournal of heat transfer > Vol. 132 N° 5 (Mai 2010) . - pp. [052403-1/8] Titre : Design and test of carbon nanotube biwick structure for high-heat-flux phase change heat transfer Type de document : texte imprimé Auteurs : Qingjun Cai, Auteur ; Chung-Lung Chen, Auteur Article en page(s) : pp. [052403-1/8] Note générale : Physique Langues : Anglais (eng) Mots-clés : Thermometer Carbon nanotube Wick structure Temperature measurement Capillarity Cooling Index. décimale : 536 Chaleur. Thermodynamique Résumé : With the increase in power consumption in compact electronic devices, passive heat transfer cooling technologies with high-heat-flux characteristics are highly desired in microelectronic industries. Carbon nanotube (CNT) clusters have high thermal conductivity, nanopore size, and large porosity and can be used as wick structure in a heat pipe heatspreader to provide high capillary force for high-heat-flux thermal management. This paper reports investigations of high-heat-flux cooling of the CNT biwick structure, associated with the development of a reliable thermometer and high performance heater. The thermometer/heater is a 100-nm-thick and 600 µm wide Z-shaped platinum wire resistor, fabricated on a thermally oxidized silicon substrate of a CNT sample to heat a 2×2 mm2 wick area. As a heater, it provides a direct heating effect without a thermal interface and is capable of high-temperature operation over 800°C. As a thermometer, reliable temperature measurement is achieved by calibrating the resistance variation versus temperature after the annealing process is applied. The thermally oxidized layer on the silicon substrate is around 1-µm-thick and pinhole-free, which ensures the platinum thermometer/heater from the severe CNT growth environments without any electrical leakage. For high-heat-flux cooling, the CNT biwick structure is composed of 250 µm tall and 100 µm wide stripelike CNT clusters with 50 µm stripe-spacers. Using 1×1 cm2 CNT biwick samples, experiments are completed in both open and saturated environments. Experimental results demonstrate 600 W/cm2 heat transfer capacity and good thermal and mass transport characteristics in the nanolevel porous media. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&smode=strresults& [...] [article] Design and test of carbon nanotube biwick structure for high-heat-flux phase change heat transfer [texte imprimé] / Qingjun Cai, Auteur ; Chung-Lung Chen, Auteur . - pp. [052403-1/8]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 5 (Mai 2010) . - pp. [052403-1/8] Mots-clés : Thermometer Carbon nanotube Wick structure Temperature measurement Capillarity Cooling Index. décimale : 536 Chaleur. Thermodynamique Résumé : With the increase in power consumption in compact electronic devices, passive heat transfer cooling technologies with high-heat-flux characteristics are highly desired in microelectronic industries. Carbon nanotube (CNT) clusters have high thermal conductivity, nanopore size, and large porosity and can be used as wick structure in a heat pipe heatspreader to provide high capillary force for high-heat-flux thermal management. This paper reports investigations of high-heat-flux cooling of the CNT biwick structure, associated with the development of a reliable thermometer and high performance heater. The thermometer/heater is a 100-nm-thick and 600 µm wide Z-shaped platinum wire resistor, fabricated on a thermally oxidized silicon substrate of a CNT sample to heat a 2×2 mm2 wick area. As a heater, it provides a direct heating effect without a thermal interface and is capable of high-temperature operation over 800°C. As a thermometer, reliable temperature measurement is achieved by calibrating the resistance variation versus temperature after the annealing process is applied. The thermally oxidized layer on the silicon substrate is around 1-µm-thick and pinhole-free, which ensures the platinum thermometer/heater from the severe CNT growth environments without any electrical leakage. For high-heat-flux cooling, the CNT biwick structure is composed of 250 µm tall and 100 µm wide stripelike CNT clusters with 50 µm stripe-spacers. Using 1×1 cm2 CNT biwick samples, experiments are completed in both open and saturated environments. Experimental results demonstrate 600 W/cm2 heat transfer capacity and good thermal and mass transport characteristics in the nanolevel porous media. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&smode=strresults& [...]

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Optimal wind–thermal generating unit commitment / Chung-Lung Chen in IEEE transactions on energy conversion, Vol. 23 N°1 (Mars 2008)  

Public ISBD [article]  inIEEE transactions on energy conversion > Vol. 23 N°1 (Mars 2008) . - pp. 273 - 280 Titre : Optimal wind–thermal generating unit commitment Type de document : texte imprimé Auteurs : Chung-Lung Chen, Auteur Année de publication : 2008 Article en page(s) : pp. 273 - 280 Note générale : Energy conversion Langues : Anglais (eng) Mots-clés : Dynamic programming  hybrid power systems  generation scheduling  thermal stations  wind Résumé : As wind power penetrations increase in isolated power systems, more innovative and sophisticated approaches to system operation will need to be adopted due to the intermittency and unpredictability of wind power generation. In this paper, a hybrid approach of combining branch and bound algorithm with a dynamic programming algorithm is developed to coordinate the wind and thermal generation scheduling problem for operating an isolated hybrid power system reliably and efficiently. Several technique constraints are applied to determine the maximum proportion of wind generator capacity that can be integrated into the system. A simplified dispatch based on the direct search method (DSM) is also introduced to relieve the computational burden further. Numerical experiments are included to understand the wind generator capacity in production cost analysis and to provide valuable information for both operational and planning problems. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4453978&sortType%3Das [...] [article] Optimal wind–thermal generating unit commitment [texte imprimé] / Chung-Lung Chen, Auteur . - 2008 . - pp. 273 - 280. Energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 23 N°1 (Mars 2008) . - pp. 273 - 280 Mots-clés : Dynamic programming  hybrid power systems  generation scheduling  thermal stations  wind Résumé : As wind power penetrations increase in isolated power systems, more innovative and sophisticated approaches to system operation will need to be adopted due to the intermittency and unpredictability of wind power generation. In this paper, a hybrid approach of combining branch and bound algorithm with a dynamic programming algorithm is developed to coordinate the wind and thermal generation scheduling problem for operating an isolated hybrid power system reliably and efficiently. Several technique constraints are applied to determine the maximum proportion of wind generator capacity that can be integrated into the system. A simplified dispatch based on the direct search method (DSM) is also introduced to relieve the computational burden further. Numerical experiments are included to understand the wind generator capacity in production cost analysis and to provide valuable information for both operational and planning problems. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4453978&sortType%3Das [...]

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