Claudiu-Florinel Bisu, Mihai Ghinea, Alain G'erard, Miron Zapciu, Marin Anica
L’apparition de vibrations, ou bien des regimes instables, est induite par l’interaction dynamique du processus de coupe avec le systeme elastique de la machine-outil dans differentes conditions de travail. L’objectif de ce travail est de developper un modele dynamique applique au processus de fraisage pour realiser la surveillance du processus, l’analyse et l’optimisation des conditions de coupe lors du contact outil/piece/machine. Pour mettre en place ce protocole et atteindre les connaissances approfondies des phenomenes dynamiques nous effectuons une etude de ceux-ci divisee en deux parties : la machine et le processus de coupe. Une analyse dynamique detaillee de la machine est obligatoire avant de modeliser les phenomenes vibratoires presents lors de la coupe.
{"title":"Analyse du comportement dynamique d’une broche de machine-outils","authors":"Claudiu-Florinel Bisu, Mihai Ghinea, Alain G'erard, Miron Zapciu, Marin Anica","doi":"10.1051/meca/2011138","DOIUrl":"https://doi.org/10.1051/meca/2011138","url":null,"abstract":"L’apparition de vibrations, ou bien des regimes instables, est induite par l’interaction dynamique du processus de coupe avec le systeme elastique de la machine-outil dans differentes conditions de travail. L’objectif de ce travail est de developper un modele dynamique applique au processus de fraisage pour realiser la surveillance du processus, l’analyse et l’optimisation des conditions de coupe lors du contact outil/piece/machine. Pour mettre en place ce protocole et atteindre les connaissances approfondies des phenomenes dynamiques nous effectuons une etude de ceux-ci divisee en deux parties : la machine et le processus de coupe. Une analyse dynamique detaillee de la machine est obligatoire avant de modeliser les phenomenes vibratoires presents lors de la coupe.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"2 1","pages":"459-467"},"PeriodicalIF":0.0,"publicationDate":"2012-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73668274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nous etudions experimentalement et numeriquement la dynamique de bulles d’air isolees traversant l’interface initialement plane entre deux liquides newtoniens. Les liquides utilises dans les experiences nous permettent d’obtenir des rapports de viscosite qui peuvent varier de deux ordres de grandeur entre les deux couches et dans une moindre mesure, de faire varier le contraste de densite et la tension interfaciale rencontres par la bulle lors de la traversee de l’interface. Deux dispositifs d’injection differents sont utilises afin d’obtenir des bulles dont les diametres s’echelonnent typiquement entre 1 mm et 2 cm et dont les plus grosses adoptent une forme torique. Nous realisons en parallele des simulations numeriques axisymetriques a l’aide de deux approches distinctes basees pour l’une sur un modele de capture d’interface (de type VOF mais sans reconstruction d’interface), pour l’autre sur un modele de Cahn-Hilliard couple aux equations de Navier-Stokes.
{"title":"Dynamique de bulles traversant l’interface séparant deux liquides","authors":"R. Bonhomme, J. Magnaudet, Bruno Piar","doi":"10.1051/MECA/2011108","DOIUrl":"https://doi.org/10.1051/MECA/2011108","url":null,"abstract":"Nous etudions experimentalement et numeriquement la dynamique de bulles d’air isolees traversant l’interface initialement plane entre deux liquides newtoniens. Les liquides utilises dans les experiences nous permettent d’obtenir des rapports de viscosite qui peuvent varier de deux ordres de grandeur entre les deux couches et dans une moindre mesure, de faire varier le contraste de densite et la tension interfaciale rencontres par la bulle lors de la traversee de l’interface. Deux dispositifs d’injection differents sont utilises afin d’obtenir des bulles dont les diametres s’echelonnent typiquement entre 1 mm et 2 cm et dont les plus grosses adoptent une forme torique. Nous realisons en parallele des simulations numeriques axisymetriques a l’aide de deux approches distinctes basees pour l’une sur un modele de capture d’interface (de type VOF mais sans reconstruction d’interface), pour l’autre sur un modele de Cahn-Hilliard couple aux equations de Navier-Stokes.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"78 1","pages":"163-167"},"PeriodicalIF":0.0,"publicationDate":"2011-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75084386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lotfi Chikh, Cédric Baradat, Philippe Poignet, F. Pierrot, Micaël Michelin
Un prototype de robot parallele actionne pneumatiquement a deux degres de liberte a ete developpe afin de rendre accessible aux petites et moyennes entreprises la robotisation de tâches qui necessiteraient le deplacement de charges de 5 a 20 kg en utilisant des verins standards moins onereux que les moteurs electriques. Apres une presentation de la structure mecanique du robot ainsi que les modeles de ses actionneurs, la strategie de commande innovante (commande predictive generalisee avec boucle interne de force ) est introduite, puis les resultats obtenus experimentalement sont presentes et analyses.
{"title":"AIR2, un robot parallèle à actionnement pneumatique à deux degrés de liberté pour les applications de prise et dépose d’objets","authors":"Lotfi Chikh, Cédric Baradat, Philippe Poignet, F. Pierrot, Micaël Michelin","doi":"10.1051/MECA/2011106","DOIUrl":"https://doi.org/10.1051/MECA/2011106","url":null,"abstract":"Un prototype de robot parallele actionne pneumatiquement a deux degres de liberte a ete developpe afin de rendre accessible aux petites et moyennes entreprises la robotisation de tâches qui necessiteraient le deplacement de charges de 5 a 20 kg en utilisant des verins standards moins onereux que les moteurs electriques. Apres une presentation de la structure mecanique du robot ainsi que les modeles de ses actionneurs, la strategie de commande innovante (commande predictive generalisee avec boucle interne de force ) est introduite, puis les resultats obtenus experimentalement sont presentes et analyses.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"21 1","pages":"239-243"},"PeriodicalIF":0.0,"publicationDate":"2011-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75302009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
On developpe dans ces travaux un outil numerique permettant de simuler le procede Friction Stir Spot Welding. Le modele est base sur un couplage fluide/solide et permet une description correcte des parties fortement malaxee et solide de la structure. Une approche ALE est utilisee avec un mouvement arbitraire defini de facon que le maillage suive la matiere dans la partie solide mais pas dans la partie pâteuse. Ceci permet la simulation de plusieurs tours de l'outil tout en suivant les bords des toles soudees durant le procede. Ce modele numerique s'appuie sur l'element fini mixte P1+/P1. Ce dernier a ete developpe avec une formulation temperature/vitesse/pression en mecanique des fluides (dans le cas d'un ecoulement laminaire incompressible et transitoire) et en mecanique des solides dans le cadre des grandes transformations. La transition fluide/solide est effectuee au moyen d'un test explicite sur une temperature moyenne par element, l'interface passant alors entre les elements du maillage. Une procedure d'actualisation de la geometrie associee a l'approche ALE est effectuee a convergence. Ce couplage a ete integre au sein d'une nouvelle option du code SYSWELD. On presente ici une premiere simulation du procede Friction Stir Spot Welding. D'autre part, deux montages specifiques sont proposes pour l'investigation du procede Friction Stir Spot Welding. Ces deux dispositifs integrent une demarche de validation globale visant a calibrer la modelisation proposee du procede. La strategie experimentale suivie est detaillee, et des premiers resultats obtenus sur un alliage d'aluminium basique sont presentes.
{"title":"Modélisation des couplages fluide/solide dans les procédés d’assemblage à haute température","authors":"Thomas Heuzé, J. Leblond, J. Bergheau","doi":"10.1051/MECA/2011113","DOIUrl":"https://doi.org/10.1051/MECA/2011113","url":null,"abstract":"On developpe dans ces travaux un outil numerique permettant de simuler le procede Friction Stir Spot Welding. Le modele est base sur un couplage fluide/solide et permet une description correcte des parties fortement malaxee et solide de la structure. Une approche ALE est utilisee avec un mouvement arbitraire defini de facon que le maillage suive la matiere dans la partie solide mais pas dans la partie pâteuse. Ceci permet la simulation de plusieurs tours de l'outil tout en suivant les bords des toles soudees durant le procede. Ce modele numerique s'appuie sur l'element fini mixte P1+/P1. Ce dernier a ete developpe avec une formulation temperature/vitesse/pression en mecanique des fluides (dans le cas d'un ecoulement laminaire incompressible et transitoire) et en mecanique des solides dans le cadre des grandes transformations. La transition fluide/solide est effectuee au moyen d'un test explicite sur une temperature moyenne par element, l'interface passant alors entre les elements du maillage. Une procedure d'actualisation de la geometrie associee a l'approche ALE est effectuee a convergence. Ce couplage a ete integre au sein d'une nouvelle option du code SYSWELD. On presente ici une premiere simulation du procede Friction Stir Spot Welding. D'autre part, deux montages specifiques sont proposes pour l'investigation du procede Friction Stir Spot Welding. Ces deux dispositifs integrent une demarche de validation globale visant a calibrer la modelisation proposee du procede. La strategie experimentale suivie est detaillee, et des premiers resultats obtenus sur un alliage d'aluminium basique sont presentes.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"22 1","pages":"183-191"},"PeriodicalIF":0.0,"publicationDate":"2011-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89700953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There has been a number of initiatives launched in the field of lubrication as potential sources of improvements in energy efficiency in a wide range of engineering products, plant and processes. Attention is being focussed on bearings to improve both performance and efficiency in fields such as automotive, machine tools, industrial and power generation plant. This paper reviews some of the background to these drives and illustrates how a novel design of adjustable fluid film hydrodynamic journal type bearing shows promise to both improve performance and save energy. Theoretical modelling and practical tests have demonstrated clear improvements over conventional fluid film bearings, along with a number of other characteristics offering benefits that may be of interest to designers and users of such bearings.
{"title":"Improved performance of hydrodynamic bearings by proactive adjustment","authors":"J. K. Martin","doi":"10.1051/MECA/2011005","DOIUrl":"https://doi.org/10.1051/MECA/2011005","url":null,"abstract":"There has been a number of initiatives launched in the field of lubrication as potential sources of improvements in energy efficiency in a wide range of engineering products, plant and processes. Attention is being focussed on bearings to improve both performance and efficiency in fields such as automotive, machine tools, industrial and power generation plant. This paper reviews some of the background to these drives and illustrates how a novel design of adjustable fluid film hydrodynamic journal type bearing shows promise to both improve performance and save energy. Theoretical modelling and practical tests have demonstrated clear improvements over conventional fluid film bearings, along with a number of other characteristics offering benefits that may be of interest to designers and users of such bearings.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"145 1","pages":"17-24"},"PeriodicalIF":0.0,"publicationDate":"2011-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82268491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Gayton, N. Gayton, Paul Beaucaire, Jean-Marc Bourinet, E. Duc, M. Lemaire, L. Gauvrit
In mass production, the customer defines the constraints of assembled products by functional and quality requirements. The functional requirements are expressed by the designer through the chosen dimensions, which are linked by linear equations in the case of a simple stack-up or non-linear equations in a more complex case. The customer quality requirements are defined by the maximum allowable number of out-of-tolerance assemblies. The aim of this paper is to prove that quality requirements can be accurately predicted in the design stage thanks to a better knowledge of the statistical characteristics of the process. The authors propose an approach named Advanced Probability based Tolerance Analysis (APTA), assessing the defect probability (called P D ) that the assembled product has of not conforming to the functional requirements. This probability depends on the requirements (nominal value, tolerance, capability levels) set by the designer for each part of the product and on the knowledge of production devices that will produce batches with variable statistical characteristics (mean value, standard deviation). The interest of the proposed methodology is shown for linear and non-linear equations related to industrial products manufactured by the RADIALL SA Company.
{"title":"APTA: advanced probability-based tolerance analysis of products","authors":"N. Gayton, N. Gayton, Paul Beaucaire, Jean-Marc Bourinet, E. Duc, M. Lemaire, L. Gauvrit","doi":"10.1051/MECA/2011014","DOIUrl":"https://doi.org/10.1051/MECA/2011014","url":null,"abstract":"In mass production, the customer defines the constraints of assembled products by functional and quality requirements. The functional requirements are expressed by the designer through the chosen dimensions, which are linked by linear equations in the case of a simple stack-up or non-linear equations in a more complex case. The customer quality requirements are defined by the maximum allowable number of out-of-tolerance assemblies. The aim of this paper is to prove that quality requirements can be accurately predicted in the design stage thanks to a better knowledge of the statistical characteristics of the process. The authors propose an approach named Advanced Probability based Tolerance Analysis (APTA), assessing the defect probability (called P D ) that the assembled product has of not conforming to the functional requirements. This probability depends on the requirements (nominal value, tolerance, capability levels) set by the designer for each part of the product and on the knowledge of production devices that will produce batches with variable statistical characteristics (mean value, standard deviation). The interest of the proposed methodology is shown for linear and non-linear equations related to industrial products manufactured by the RADIALL SA Company.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"22 1","pages":"71-85"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76630121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L’article propose une methodologie pour exploiter les mesures de capabilite des procedes de fabrication dans le calcul des tolerances de localisation d’un ensemble d’elements geometriques selon les standards ISO 1101 et ASME Y14.5 avec une approche statistique. Le nombre d’elements geometriques etudies, les erreurs systematique et aleatoire du procede de fabrication seront retenues et incluses dans l’approche. Un modele mathematique explicite est developpe dans le but d’identifier les fonctions de distribution statistique pour differents types de tolerances de localisation. A partir de ces distributions, nous presentons une methodologie servant a estimer les valeurs des tolerances qui permettent de rencontrer un seuil de conformite pretabli, et vice versa. L’article presente egalement une serie d’abaques permettant un usage industriel simple et commode. Plusieurs exemples de calculs sont illustres et un cas d’etude y est presente.
{"title":"Exploitation des études de capabilité dans le calcul statistique des tolérances géométriques de localisation","authors":"Antoine Tahan, S. Lévesque","doi":"10.1051/MECA/2011140","DOIUrl":"https://doi.org/10.1051/MECA/2011140","url":null,"abstract":"L’article propose une methodologie pour exploiter les mesures de capabilite des procedes de fabrication dans le calcul des tolerances de localisation d’un ensemble d’elements geometriques selon les standards ISO 1101 et ASME Y14.5 avec une approche statistique. Le nombre d’elements geometriques etudies, les erreurs systematique et aleatoire du procede de fabrication seront retenues et incluses dans l’approche. Un modele mathematique explicite est developpe dans le but d’identifier les fonctions de distribution statistique pour differents types de tolerances de localisation. A partir de ces distributions, nous presentons une methodologie servant a estimer les valeurs des tolerances qui permettent de rencontrer un seuil de conformite pretabli, et vice versa. L’article presente egalement une serie d’abaques permettant un usage industriel simple et commode. Plusieurs exemples de calculs sont illustres et un cas d’etude y est presente.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"14 1","pages":"503-512"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82646239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Several studies have been carried out in order to describe the impact of water-contaminated lubricants on lubrication performance. One approach considers the water-contaminated oil as a homogeneous lubricant with physical characteristics varying with water concentration. The presented work is being achieved in order to experimentally validate this theory. First investigations showed that the variation of contaminated lubricant viscosity has the most significant effect on lubricating performance. Consequently, the lubricant viscosity is the only parameter taken into account in this study. Thus, based on the rheological measurements, water-in-oil emulsion viscosity has been modelled according to water concentration and temperature. Water concentration was considered relatively to total mass of oil: the mass concentration varied then from 0 to 7% and temperature from 10 to 80 °C. Viscosity modelling was then used to perform the numerical simulations of a hydrodynamic thrust bearing supplied with water contaminated oil. Finally, the experimental validation will be done by measuring various bearing characteristics like the film/pad temperature, the film thickness and the friction torque on a tilting pad thrust bearing test rig.
{"title":"Impact of lubricant contamination with water on hydrodynamic thrust bearing performance","authors":"E. Harika, M. Helene, J. Bouyer, M. Fillon","doi":"10.1051/MECA/2011120","DOIUrl":"https://doi.org/10.1051/MECA/2011120","url":null,"abstract":"Several studies have been carried out in order to describe the impact of water-contaminated lubricants on lubrication performance. One approach considers the water-contaminated oil as a homogeneous lubricant with physical characteristics varying with water concentration. The presented work is being achieved in order to experimentally validate this theory. First investigations showed that the variation of contaminated lubricant viscosity has the most significant effect on lubricating performance. Consequently, the lubricant viscosity is the only parameter taken into account in this study. Thus, based on the rheological measurements, water-in-oil emulsion viscosity has been modelled according to water concentration and temperature. Water concentration was considered relatively to total mass of oil: the mass concentration varied then from 0 to 7% and temperature from 10 to 80 °C. Viscosity modelling was then used to perform the numerical simulations of a hydrodynamic thrust bearing supplied with water contaminated oil. Finally, the experimental validation will be done by measuring various bearing characteristics like the film/pad temperature, the film thickness and the friction torque on a tilting pad thrust bearing test rig.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"33 14 1","pages":"353-359"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82831986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Tan, M. Stoschka, M. Riedler, W. Eichlseder, F. Romagnoli, Vinícius Rondon
An improvement in the life time calculation is aspired by the characterisation of the life time behaviour of a typically lightweight aircraft titanium alloy by describing the microstructure. Therefore, extensive research on a Ti-6-4 fitting element has been carried out. In addition to static tensile tests, rotating bending tests and fracture mechanical tests, component tests with constant and variable load were performed. Simultaneously, the microstructures of the specimens and tested components are extensively analysed at several points including the lug area, as well as, the specimen’s microstructure taken out of the lower link fitting. A common consideration of life time results as well as results of the microstructure in the life time calculation shows the possibilities for more precise life time estimation.
{"title":"Material and component investigations on a Ti-6-4 fitting element","authors":"W. Tan, M. Stoschka, M. Riedler, W. Eichlseder, F. Romagnoli, Vinícius Rondon","doi":"10.1051/MECA/2011130","DOIUrl":"https://doi.org/10.1051/MECA/2011130","url":null,"abstract":"An improvement in the life time calculation is aspired by the characterisation of the life time behaviour of a typically lightweight aircraft titanium alloy by describing the microstructure. Therefore, extensive research on a Ti-6-4 fitting element has been carried out. In addition to static tensile tests, rotating bending tests and fracture mechanical tests, component tests with constant and variable load were performed. Simultaneously, the microstructures of the specimens and tested components are extensively analysed at several points including the lug area, as well as, the specimen’s microstructure taken out of the lower link fitting. A common consideration of life time results as well as results of the microstructure in the life time calculation shows the possibilities for more precise life time estimation.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"1 1","pages":"361-378"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80811357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L’assemblage de certaines pieces metalliques qu’on peut rencontrer dans l’industrie (nucleaire, spatiale, ...), engendre souvent un chemin de fuite qui peut laisser passer un fluide. L’etude suivante a pour objet la comprehension de la phenomenologie d’un ecoulement confine traversant le voisinage du point critique et son influence sur le debit de fuite. Ce probleme d’etancheite a ete limite aux situations stationnaires et visqueuses. Le chemin de filtration a ete assimile a un capillaire dont la paroi est maintenue a la temperature critique. Une difference de pression a ete imposee entre une entree supercritique et une sortie subcritique. L’approche phenomenologique a permis de mettre en evidence la presence d’une zone de transition au passage du point critique. Dans cette region de forte dilatation on a montre l’existence d’un couplage thermo-dynamique et le role joue par la convection thermique qui associe la conduction pour assurer le transport de chaleur. On montre que la progression du fluide vers l’exterieur est ralentie par un effet bouchon.
{"title":"Étanchéités statiques des écoulements de filtration au voisinage du point critique","authors":"Raouf Khelalfa, J. Darrozes, J. Durastanti","doi":"10.1051/MECA/2011009","DOIUrl":"https://doi.org/10.1051/MECA/2011009","url":null,"abstract":"L’assemblage de certaines pieces metalliques qu’on peut rencontrer dans l’industrie (nucleaire, spatiale, ...), engendre souvent un chemin de fuite qui peut laisser passer un fluide. L’etude suivante a pour objet la comprehension de la phenomenologie d’un ecoulement confine traversant le voisinage du point critique et son influence sur le debit de fuite. Ce probleme d’etancheite a ete limite aux situations stationnaires et visqueuses. Le chemin de filtration a ete assimile a un capillaire dont la paroi est maintenue a la temperature critique. Une difference de pression a ete imposee entre une entree supercritique et une sortie subcritique. L’approche phenomenologique a permis de mettre en evidence la presence d’une zone de transition au passage du point critique. Dans cette region de forte dilatation on a montre l’existence d’un couplage thermo-dynamique et le role joue par la convection thermique qui associe la conduction pour assurer le transport de chaleur. On montre que la progression du fluide vers l’exterieur est ralentie par un effet bouchon.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"7 1","pages":"123-130"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72976481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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