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Heat flux and temperature field estimation using differential interferometer / S. Prasanna 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. [094502-1/4] Titre : Heat flux and temperature field estimation using differential interferometer Type de document : texte imprimé Auteurs : S. Prasanna, Auteur ; S. P. Venkateshan, Auteur Article en page(s) : pp. [094502-1/4] Note générale : Physique Langues : Anglais (eng) Mots-clés : Differential  interferometer  Digital  analysis  Thermal  visualization Index. décimale : 536 Chaleur. Thermodynamique Résumé : A new methodology based on least-squares approach has been developed to estimate the temperature field from an interferogram recorded using a Differential interferometer (DI). The interferograms are digitally evaluated using two dimensional Fourier transforms to retrieve the temperature gradient field. Temperature field is constructed by fitting a cubic spline to the first derivatives data. The methodology has been applied to both experimental and synthetic interferograms. Both convective heat flux and temperature field were predicted accurately. The role of image noise and errors in the temperature measurements on the temperature field estimation have been studied with the aid of synthetic interferograms. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Heat flux and temperature field estimation using differential interferometer [texte imprimé] / S. Prasanna, Auteur ; S. P. Venkateshan, Auteur . - pp. [094502-1/4]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 9 (Septembre 2010) . - pp. [094502-1/4] Mots-clés : Differential  interferometer  Digital  analysis  Thermal  visualization Index. décimale : 536 Chaleur. Thermodynamique Résumé : A new methodology based on least-squares approach has been developed to estimate the temperature field from an interferogram recorded using a Differential interferometer (DI). The interferograms are digitally evaluated using two dimensional Fourier transforms to retrieve the temperature gradient field. Temperature field is constructed by fitting a cubic spline to the first derivatives data. The methodology has been applied to both experimental and synthetic interferograms. Both convective heat flux and temperature field were predicted accurately. The role of image noise and errors in the temperature measurements on the temperature field estimation have been studied with the aid of synthetic interferograms. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Investigations on multimode heat transfer from a heated vertical plate / R. Krishna Sabareesh in Journal of heat transfer, Vol. 132 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 3 (Mars 2010) . - pp. [032501-1/8] Titre : Investigations on multimode heat transfer from a heated vertical plate Type de document : texte imprimé Auteurs : R. Krishna Sabareesh, Auteur ; S. Prasanna, Auteur ; S. P. Venkateshan, Auteur Article en page(s) : pp. [032501-1/8] Note générale : Physique Langues : Anglais (eng) Mots-clés : Multimode  heat  transfer  Interfermeter  Thermal  conductivity  Emissivity  Asymptotic  limits Index. décimale : 536 Chaleur. Thermodynamique Résumé : The interaction of surface radiation and conduction with natural convection heat transfer from a vertical flat plate assembly, with an embedded heater, has been investigated, both experimentally (using differential interferometer) and numerically (using FLUENT), in the present work. In the absence of radiation, the asymptotic limits that can be attained by the heated plate are isothermal and isoflux conditions. High values of plate thermal conductivity tend to make the surface isothermal, where as, lower values of thermal conductivity tend to make it isoflux. Irrespective of the thermal conductivity of the plate, an increase in the emissivity reduces the average temperature of the plate and brings the plate toward isothermal condition. A new methodology has also been proposed to determine the thermophysical properties, emissivity and thermal conductivity, the consistency of which is tested by carrying out experiments for various heat inputs and comparing the estimated values with those available in literature. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Investigations on multimode heat transfer from a heated vertical plate [texte imprimé] / R. Krishna Sabareesh, Auteur ; S. Prasanna, Auteur ; S. P. Venkateshan, Auteur . - pp. [032501-1/8]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 3 (Mars 2010) . - pp. [032501-1/8] Mots-clés : Multimode  heat  transfer  Interfermeter  Thermal  conductivity  Emissivity  Asymptotic  limits Index. décimale : 536 Chaleur. Thermodynamique Résumé : The interaction of surface radiation and conduction with natural convection heat transfer from a vertical flat plate assembly, with an embedded heater, has been investigated, both experimentally (using differential interferometer) and numerically (using FLUENT), in the present work. In the absence of radiation, the asymptotic limits that can be attained by the heated plate are isothermal and isoflux conditions. High values of plate thermal conductivity tend to make the surface isothermal, where as, lower values of thermal conductivity tend to make it isoflux. Irrespective of the thermal conductivity of the plate, an increase in the emissivity reduces the average temperature of the plate and brings the plate toward isothermal condition. A new methodology has also been proposed to determine the thermophysical properties, emissivity and thermal conductivity, the consistency of which is tested by carrying out experiments for various heat inputs and comparing the estimated values with those available in literature. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Natural convection in a partially heat generating rod bundle inside an enclosure / D. Jaya Krishna in Journal of heat transfer, Vol. 132 N° 10 (Octobre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 10 (Octobre 2010) . - pp.[102501/1-11] Titre : Natural convection in a partially heat generating rod bundle inside an enclosure Type de document : texte imprimé Auteurs : D. Jaya Krishna, Auteur ; M. R. Thansekhar, Auteur ; S. P. Venkateshan, Auteur Année de publication : 2010 Article en page(s) : pp.[102501/1-11] Note générale : Physique Langues : Anglais (eng) Mots-clés : Natural  convection  Non-darcy  porous  medium  Heat  generating  rod  bundle  Partially  heat  generating  enclosure Index. décimale : 536 Chaleur. Thermodynamique Résumé : Buoyancy induced flows in a partially heat generating rod bundle enclosed inside a tall cavity are investigated. First, a detailed experimental study is carried out, and the thermal hydraulics is analyzed at different power inputs and boundary cooling rates of the enclosure. Later, a generalized non-Darcy simulation is developed using a heat generating orthotropic porous media approach and is compared with the experimental results. The results of a numerical simulation for natural convection in enclosed partially heat generating rod bundles satisfactorily predict the temperature distribution within the rod bundle. Finally, a parametric study is carried out by varying the porosity (pitch to diameter ratio of the rod bundle) of the considered enclosure for the understanding of flow physics and heat transfer in such applications. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Natural convection in a partially heat generating rod bundle inside an enclosure [texte imprimé] / D. Jaya Krishna, Auteur ; M. R. Thansekhar, Auteur ; S. P. Venkateshan, Auteur . - 2010 . - pp.[102501/1-11]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 10 (Octobre 2010) . - pp.[102501/1-11] Mots-clés : Natural  convection  Non-darcy  porous  medium  Heat  generating  rod  bundle  Partially  heat  generating  enclosure Index. décimale : 536 Chaleur. Thermodynamique Résumé : Buoyancy induced flows in a partially heat generating rod bundle enclosed inside a tall cavity are investigated. First, a detailed experimental study is carried out, and the thermal hydraulics is analyzed at different power inputs and boundary cooling rates of the enclosure. Later, a generalized non-Darcy simulation is developed using a heat generating orthotropic porous media approach and is compared with the experimental results. The results of a numerical simulation for natural convection in enclosed partially heat generating rod bundles satisfactorily predict the temperature distribution within the rod bundle. Finally, a parametric study is carried out by varying the porosity (pitch to diameter ratio of the rod bundle) of the considered enclosure for the understanding of flow physics and heat transfer in such applications. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]