Numerical and experimental investigation of laminar channel flow with a transparent wall / Jing He in Journal of heat transfer, Vol. 133 N° 6 (Juin 2011)  

Public ISBD [article]  inJournal of heat transfer > Vol. 133 N° 6 (Juin 2011) . - pp. [061701/1-9] Titre : Numerical and experimental investigation of laminar channel flow with a transparent wall Type de document : texte imprimé Auteurs : Jing He, Auteur ; Liping Liu, Auteur ; Anthony M. Jacobi, Auteur Année de publication : 2011 Article en page(s) : pp. [061701/1-9] Note générale : Physique Langues : Anglais (eng) Mots-clés : Laminar channel flow Conjugate heat transfer Transparent wall Infrared thermography Index. décimale : 536 Chaleur. Thermodynamique Résumé : A numerical and experimental investigation is undertaken for developing laminar flow in a duct with one opaque, uniformly heated wall and one transparent wall. In the numerical model, mixed convection, radiative exchange, as well as two-dimensional conduction in the substrate are considered. Experiments are conducted in a high-aspect-ratio rectangular channel using infrared thermography to validate the numerical model and visualize the temperature field on a heated surface. An extended parametric study using the validated model is also carried out to assess the impact of channel height, and thermal conductivity and thickness of the substrate. For a channel height of H=6 mm and a heating power of qs=257 W/m2, as Re increases from 150 to 940 the fraction of heat transfer by convection from the heated surface rises from 65% to 79%. At Re=150, as H increases from 6 mm to 25 mm, radiation from the heated surface increases from 35% to 70% of the total heating power. The influence of substrate conductivity and thickness on local flux distributions is limited to regions near the channel inlet and outlet. Over the entire parametric space considered, radiation loss from the interior duct surfaces to the inlet and outlet apertures is less than 2% of the total heat input and thus unimportant. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Numerical and experimental investigation of laminar channel flow with a transparent wall [texte imprimé] / Jing He, Auteur ; Liping Liu, Auteur ; Anthony M. Jacobi, Auteur . - 2011 . - pp. [061701/1-9]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 6 (Juin 2011) . - pp. [061701/1-9] Mots-clés : Laminar channel flow Conjugate heat transfer Transparent wall Infrared thermography Index. décimale : 536 Chaleur. Thermodynamique Résumé : A numerical and experimental investigation is undertaken for developing laminar flow in a duct with one opaque, uniformly heated wall and one transparent wall. In the numerical model, mixed convection, radiative exchange, as well as two-dimensional conduction in the substrate are considered. Experiments are conducted in a high-aspect-ratio rectangular channel using infrared thermography to validate the numerical model and visualize the temperature field on a heated surface. An extended parametric study using the validated model is also carried out to assess the impact of channel height, and thermal conductivity and thickness of the substrate. For a channel height of H=6 mm and a heating power of qs=257 W/m2, as Re increases from 150 to 940 the fraction of heat transfer by convection from the heated surface rises from 65% to 79%. At Re=150, as H increases from 6 mm to 25 mm, radiation from the heated surface increases from 35% to 70% of the total heating power. The influence of substrate conductivity and thickness on local flux distributions is limited to regions near the channel inlet and outlet. Over the entire parametric space considered, radiation loss from the interior duct surfaces to the inlet and outlet apertures is less than 2% of the total heat input and thus unimportant. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

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Research on the effect of whole cylinder block on EHL performance of main bearings considering crankshaft deformation for internal combustion engine / Jun Sun in Transactions of the ASME . Journal of tribology, Vol. 132 N° 4 (Octobre 2010)  

Public ISBD [article]  inTransactions of the ASME . Journal of tribology > Vol. 132 N° 4 (Octobre 2010) . - 06 p. Titre : Research on the effect of whole cylinder block on EHL performance of main bearings considering crankshaft deformation for internal combustion engine Type de document : texte imprimé Auteurs : Jun Sun, Auteur ; Xiaoxia Cai, Auteur ; Liping Liu, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Elastic deformation Elastodynamics Heat engines Hydrodynamics Lubrication Machine bearings Shafts Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In this paper, the analyses of elastohydrodynamic lubrication (EHL) of crankshaft bearings considering the deformation of the whole cylinder block and crankshaft under load were carried out for the crankshaft bearing system of a four-stroke four-cylinder internal combustion engine. The lubrication of crankshaft bearing was analyzed by dynamic method. The deformation of bearing surface under pressure of oil film was calculated by compliance matrix method. The results show that when the crankshaft deformation under load is considered, compared with the results of not considering the deformation of cylinder block, the maximum film pressure decreases, the minimum film thickness increases, and the end leakage flow-rate and frictional coefficient of journal surface change little in an engine working cycle when considering the deformation of cylinder block. The models of the whole cylinder block and the single main bearing housing were used, respectively, to calculate the deformation of main bearing surface in the analyses. The results show that the calculation accuracy of the elastohydrodynamic lubrication analyses of crankshaft main bearings can be met basically by applying the simple model based on the single main bearing housing to calculate the elastic deformation of main bearing surface. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...] [article] Research on the effect of whole cylinder block on EHL performance of main bearings considering crankshaft deformation for internal combustion engine [texte imprimé] / Jun Sun, Auteur ; Xiaoxia Cai, Auteur ; Liping Liu, Auteur . - 2011 . - 06 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 132 N° 4 (Octobre 2010) . - 06 p. Mots-clés : Elastic deformation Elastodynamics Heat engines Hydrodynamics Lubrication Machine bearings Shafts Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In this paper, the analyses of elastohydrodynamic lubrication (EHL) of crankshaft bearings considering the deformation of the whole cylinder block and crankshaft under load were carried out for the crankshaft bearing system of a four-stroke four-cylinder internal combustion engine. The lubrication of crankshaft bearing was analyzed by dynamic method. The deformation of bearing surface under pressure of oil film was calculated by compliance matrix method. The results show that when the crankshaft deformation under load is considered, compared with the results of not considering the deformation of cylinder block, the maximum film pressure decreases, the minimum film thickness increases, and the end leakage flow-rate and frictional coefficient of journal surface change little in an engine working cycle when considering the deformation of cylinder block. The models of the whole cylinder block and the single main bearing housing were used, respectively, to calculate the deformation of main bearing surface in the analyses. The results show that the calculation accuracy of the elastohydrodynamic lubrication analyses of crankshaft main bearings can be met basically by applying the simple model based on the single main bearing housing to calculate the elastic deformation of main bearing surface. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...]

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