Documents disponibles écrits par cet auteur

Development of a micro thermal sensor for real-time monitoring of lubricating oil concentration / Jonggan Hong in International journal of refrigeration, Vol. 34 N° 1 (Janvier 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 1 (Janvier 2011) . - pp. 374-382 Titre : Development of a micro thermal sensor for real-time monitoring of lubricating oil concentration Titre original : Développement d'un capteur microthermique pour le suivi en temps réel de la concentration en huile lubrifiante Type de document : texte imprimé Auteurs : Jonggan Hong, Auteur ; Young Soo Chang, Auteur ; Dongsik Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 374-382 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Analysis  Development  Sensor  Measurement-concentration  Concentration  Oil  Refrigerant-concentration Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : We report development of a micro thermal sensor and sensing techniques for monitoring the oil concentration in a refrigeration system. The sensor acquires the thermal response of the mixture to ac heating and then the concentration can be determined using one of the two different methods. In the first method, the thermal conductivity of the mixture is obtained using the three-omega method and the concentration is determined using the correlation between the mixture concentration and thermal conductivity. In the alternative fast-detection method, the concentration is determined by directly calibrating the sensor output signal to the mixture concentration. The performance of the sensor was tested using the R410A/polyvinyl ether (PVE) oil mixture. The uncertainty of the oil concentration measurement was estimated to be 5.8–7.3 wt.%, depending on the sensing scheme. Especially, the simple structure of the sensor makes the technique cost effective and adequate for miniaturization, i.e., for installation in a limited space. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001556 [article] Development of a micro thermal sensor for real-time monitoring of lubricating oil concentration = Développement d'un capteur microthermique pour le suivi en temps réel de la concentration en huile lubrifiante [texte imprimé] / Jonggan Hong, Auteur ; Young Soo Chang, Auteur ; Dongsik Kim, Auteur . - 2011 . - pp. 374-382. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 1 (Janvier 2011) . - pp. 374-382 Mots-clés : Analysis  Development  Sensor  Measurement-concentration  Concentration  Oil  Refrigerant-concentration Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : We report development of a micro thermal sensor and sensing techniques for monitoring the oil concentration in a refrigeration system. The sensor acquires the thermal response of the mixture to ac heating and then the concentration can be determined using one of the two different methods. In the first method, the thermal conductivity of the mixture is obtained using the three-omega method and the concentration is determined using the correlation between the mixture concentration and thermal conductivity. In the alternative fast-detection method, the concentration is determined by directly calibrating the sensor output signal to the mixture concentration. The performance of the sensor was tested using the R410A/polyvinyl ether (PVE) oil mixture. The uncertainty of the oil concentration measurement was estimated to be 5.8–7.3 wt.%, depending on the sensing scheme. Especially, the simple structure of the sensor makes the technique cost effective and adequate for miniaturization, i.e., for installation in a limited space. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001556

Measuring the thermal conductivity of flowing liquid samples using the three omega method / Jonggan Hong in Journal of heat transfer, Vol 134 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol 134 N° 9 (Septembre 2012) . - 07 p. Titre : Measuring the thermal conductivity of flowing liquid samples using the three omega method Type de document : texte imprimé Auteurs : Jonggan Hong, Auteur ; Dongsik Kim, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : convection;  liquid;  thermal  conductivity  measurement;  thermal  wave;  three  omega  method Index. décimale : 536 Chaleur. Thermodynamique Résumé : The thermal conductivity of a liquid is generally measured under conditions that suppress bulk flow in the sample. However, in situ measurement of the thermal conductivity of a flowing liquid would be useful in various scientific and engineering applications. This work demonstrates that a thermal wave technique, such as the three omega method, can effectively measure the thermal conductivity of flowing liquid if the frequency range is adjusted such that the thermal boundary layer is sufficiently thinner than the momentum boundary layer. A new dimensionless number was defined to assess the convection effects, and a criterion for thermal conductivity measurements was obtained for water flowing in a circular tube. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000009 [...] [article] Measuring the thermal conductivity of flowing liquid samples using the three omega method [texte imprimé] / Jonggan Hong, Auteur ; Dongsik Kim, Auteur . - 2012 . - 07 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol 134 N° 9 (Septembre 2012) . - 07 p. Mots-clés : convection;  liquid;  thermal  conductivity  measurement;  thermal  wave;  three  omega  method Index. décimale : 536 Chaleur. Thermodynamique Résumé : The thermal conductivity of a liquid is generally measured under conditions that suppress bulk flow in the sample. However, in situ measurement of the thermal conductivity of a flowing liquid would be useful in various scientific and engineering applications. This work demonstrates that a thermal wave technique, such as the three omega method, can effectively measure the thermal conductivity of flowing liquid if the frequency range is adjusted such that the thermal boundary layer is sufficiently thinner than the momentum boundary layer. A new dimensionless number was defined to assess the convection effects, and a criterion for thermal conductivity measurements was obtained for water flowing in a circular tube. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000009 [...]