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Effect of rotation on heat/mass transfer for an impingement/effusion cooling system / Sung Kook Hong in Journal of heat transfer, Vol. 132 N° 11 (Novembre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 11 (Novembre 2010) . - pp. [114501-1/3] Titre : Effect of rotation on heat/mass transfer for an impingement/effusion cooling system Type de document : texte imprimé Auteurs : Sung Kook Hong, Auteur ; Dong Hyun Lee, Auteur ; Hyung Hee Cho, Auteur Année de publication : 2010 Article en page(s) : pp. [114501-1/3] Note générale : Physique Langues : Anglais (eng) Mots-clés : Impingement/effusion  cooling  Gas  turbine  Heat  transfer  Coriolis  force  Rotation Index. décimale : 536 Chaleur. Thermodynamique Résumé : In the present study, the effects of the rotating direction on heat/mass transfer in an impingement/effusion cooling system were investigated. The experiments were carried out with three different jet orientations relative to the axis of rotation and two plate spacing. For high H/d with an orthogonal jet orientation, low and nonuniform heat/mass transfer occurred between the effusion holes since the impinging jet was deflected by the Coriolis force. For a small H/d, the jet deflection effect was diminished, and rotation enhanced the heat/mass transfer in the stagnation region. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Effect of rotation on heat/mass transfer for an impingement/effusion cooling system [texte imprimé] / Sung Kook Hong, Auteur ; Dong Hyun Lee, Auteur ; Hyung Hee Cho, Auteur . - 2010 . - pp. [114501-1/3]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 11 (Novembre 2010) . - pp. [114501-1/3] Mots-clés : Impingement/effusion  cooling  Gas  turbine  Heat  transfer  Coriolis  force  Rotation Index. décimale : 536 Chaleur. Thermodynamique Résumé : In the present study, the effects of the rotating direction on heat/mass transfer in an impingement/effusion cooling system were investigated. The experiments were carried out with three different jet orientations relative to the axis of rotation and two plate spacing. For high H/d with an orthogonal jet orientation, low and nonuniform heat/mass transfer occurred between the effusion holes since the impinging jet was deflected by the Coriolis force. For a small H/d, the jet deflection effect was diminished, and rotation enhanced the heat/mass transfer in the stagnation region. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Local heat/mass transfer and friction loss measurement in a rotating matrix cooling channel / In Taek Oh in Journal of heat transfer, Vol. 134 N° 1 (Janvier 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 1 (Janvier 2012) . - 09 p. Titre : Local heat/mass transfer and friction loss measurement in a rotating matrix cooling channel Type de document : texte imprimé Auteurs : In Taek Oh, Auteur ; Kyung Min Kim, Auteur ; Dong Hyun Lee, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : Heat transfer Langues : Anglais (eng) Mots-clés : Channel  flow  Gas  turbines  Heat  transfer  Mass  transfer  Rotational  flow  Swirling  flow  Turbulence Index. décimale : 536 Chaleur. Thermodynamique Résumé : The present investigation provides detailed local heat/mass transfer and pressure drop characteristics in a matrix cooling channel, under rotating conditions. The matrix channel had cooling subpassages with crossing angles of 45 deg. The detailed heat/mass transfer coefficients were measured via the naphthalene sublimation method, and pressure drops were also obtained. The experiments were conducted for various Reynolds numbers (10,500 to 44,000) and rotation numbers (0.0 to 0.8). In the stationary case, the heat transfer characteristics were dominated by turning, impinging, and swirling flow, induced by the matrix channel geometry. Average heat/mass transfer coefficients on the leading and trailing surfaces in the stationary channel were approximately 2.1 times greater than those in a smooth channel. In the rotating cases, the effect of rotation on heat/mass transfer characteristics differed from that of typical rotating channels with radially outward flow. As the rotation number increased, the Sherwood number ratios increased on the leading surfaces but changed only slightly on the trailing surfaces. The thermal performance factors increased with rotation number due to the increased Sherwood number ratios and decreased friction factor ratios. DEWEY : 536 ISSN : 0022-1481 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013400 [...] [article] Local heat/mass transfer and friction loss measurement in a rotating matrix cooling channel [texte imprimé] / In Taek Oh, Auteur ; Kyung Min Kim, Auteur ; Dong Hyun Lee, Auteur . - 2012 . - 09 p. Heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 1 (Janvier 2012) . - 09 p. Mots-clés : Channel  flow  Gas  turbines  Heat  transfer  Mass  transfer  Rotational  flow  Swirling  flow  Turbulence Index. décimale : 536 Chaleur. Thermodynamique Résumé : The present investigation provides detailed local heat/mass transfer and pressure drop characteristics in a matrix cooling channel, under rotating conditions. The matrix channel had cooling subpassages with crossing angles of 45 deg. The detailed heat/mass transfer coefficients were measured via the naphthalene sublimation method, and pressure drops were also obtained. The experiments were conducted for various Reynolds numbers (10,500 to 44,000) and rotation numbers (0.0 to 0.8). In the stationary case, the heat transfer characteristics were dominated by turning, impinging, and swirling flow, induced by the matrix channel geometry. Average heat/mass transfer coefficients on the leading and trailing surfaces in the stationary channel were approximately 2.1 times greater than those in a smooth channel. In the rotating cases, the effect of rotation on heat/mass transfer characteristics differed from that of typical rotating channels with radially outward flow. As the rotation number increased, the Sherwood number ratios increased on the leading surfaces but changed only slightly on the trailing surfaces. The thermal performance factors increased with rotation number due to the increased Sherwood number ratios and decreased friction factor ratios. DEWEY : 536 ISSN : 0022-1481 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013400 [...]

The static performance analysis of foil journal bearings considering three-dimensional shape of the foil structure / Dong Hyun Lee in Transactions of the ASME . Journal of tribology, Vol. 130 n°3 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 130 n°3 (Juillet 2008) . - 10 p. Titre : The static performance analysis of foil journal bearings considering three-dimensional shape of the foil structure Type de document : texte imprimé Auteurs : Dong Hyun Lee, Auteur ; Young-Cheol Kim, Auteur ; Kyung-Woong Kim, Auteur Année de publication : 2008 Article en page(s) : 10 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Stress  Bearings  Finite  element  analysis  Deflection  Film  thickness  Shapes  Stiffness  Pressure  Thickness  Journal  bearings Résumé : To obtain the foil bearing characteristics, the fluid film pressure must be coupled with the elastic deformation of the foil structure. However, all of the structural models thus far have simplified the foil structure without consideration of its three-dimensional shape. In this study, a finite element foil structural model is proposed that takes into consideration the three-dimensional foil shape. Using the proposed model, the deflections of interconnected bumps are compared to those of separated bumps, and the minimum film thickness determined from the proposed structural models is compared to those of previous models. In addition, the effects of the top foil and bump foil thickness on the foil bearing static performance are evaluated. The results of the study show that the three-dimensional shape of the foil structure should be considered for accurate predictions of foil bearing performances and that too thin top foil or bump foil thickness may lead to a significant decrease in the load capacity. In addition, the foil stiffness variation does not increase the load capacity much under a simple foil structure. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468056 [article] The static performance analysis of foil journal bearings considering three-dimensional shape of the foil structure [texte imprimé] / Dong Hyun Lee, Auteur ; Young-Cheol Kim, Auteur ; Kyung-Woong Kim, Auteur . - 2008 . - 10 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 130 n°3 (Juillet 2008) . - 10 p. Mots-clés : Stress  Bearings  Finite  element  analysis  Deflection  Film  thickness  Shapes  Stiffness  Pressure  Thickness  Journal  bearings Résumé : To obtain the foil bearing characteristics, the fluid film pressure must be coupled with the elastic deformation of the foil structure. However, all of the structural models thus far have simplified the foil structure without consideration of its three-dimensional shape. In this study, a finite element foil structural model is proposed that takes into consideration the three-dimensional foil shape. Using the proposed model, the deflections of interconnected bumps are compared to those of separated bumps, and the minimum film thickness determined from the proposed structural models is compared to those of previous models. In addition, the effects of the top foil and bump foil thickness on the foil bearing static performance are evaluated. The results of the study show that the three-dimensional shape of the foil structure should be considered for accurate predictions of foil bearing performances and that too thin top foil or bump foil thickness may lead to a significant decrease in the load capacity. In addition, the foil stiffness variation does not increase the load capacity much under a simple foil structure. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468056