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Etude des écoulements turbulents et du transport des particules solides dans des conduites comportant une singularité. / Farid Gaci  

Public ISBD Titre : Etude des écoulements turbulents et du transport des particules solides dans des conduites comportant une singularité. Type de document : texte imprimé Auteurs : Farid Gaci, Auteur ; Zoubir Nemouchi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 156 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Génie Mécanique Tags : Ecoulement interne  conduite courbe  nombre de Dean  approche LES  coefficient de frottement  nombre de Nusselt  Internal flow  curved duct  Dean number  LES approach  friction coefficient  Nusselt number  الحركة الداخلية  القناة المنحنية  عدد دين  مقاربة  LESمعامل الاحتكاك  رقم نوسلت Index. décimale : 620 Génie Mécanique Résumé : The present work is a contribution to the study, by numerical simulation, of the characteristics of stationary and transient internal flows of Newtonian fluids and the transport of solid particles occurring in different pipes with singularities. In the first part of this doctoral thesis, the main objective is to analyze the three-dimensional temporal evolution of vortex spatial structures and to highlight the sequence of bifurcation of laminar flow in main and additional counter-rotating cells caused by the duct curvature and for different numbers of Dean. Moreover, with regard to the dynamic and thermal behaviors of the flow, it is the coefficient of friction Cf and the Nusselt number Nu that have been evaluated in order to examine the analogy that may exist between these two parameters along the bent part of the pipe. The effects of the Dean number and the curvature ratio of the pipe are presented and discussed. The second part consists of evaluating, first, the performance of turbulence models based on the RANS approach and bringing to light the adequate numerical model allowing to better simulate the internal flow through square cross-sections curved ducts. The Large Eddy Simulation (LES) approach is then used to simulate the flow of fluid through a 90° bend with a square cross-section for three different Dean numbers in order to explore unsteady turbulent flow phenomena despite its excessive numerical cost. Statistical and filtered parameters characterizing the three-dimensional dynamic and thermal behaviours of the turbulent flow are analysed. Special attention is paid to the effects of secondary flows obtained by the different approaches and the complex unsteady coherent eddy structures captured by the LES approach, on the non-homogeneous distributions of friction and heat transfer on the internal, external and lateral walls of the curved duct. In addition, an additional non-exhaustive study was presented. It deals with the injection of particles. These particles were injected into a curved pipe and the wall erosion rate was evaluated for different Reynolds numbers and particle sizes. Diplôme : Doctorat en sciences En ligne : ../theses/gmecanique/GAC7308.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=10923 Etude des écoulements turbulents et du transport des particules solides dans des conduites comportant une singularité. [texte imprimé] / Farid Gaci, Auteur ; Zoubir Nemouchi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 156 f. ; 30 cm. 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Génie Mécanique Tags : Ecoulement interne  conduite courbe  nombre de Dean  approche LES  coefficient de frottement  nombre de Nusselt  Internal flow  curved duct  Dean number  LES approach  friction coefficient  Nusselt number  الحركة الداخلية  القناة المنحنية  عدد دين  مقاربة  LESمعامل الاحتكاك  رقم نوسلت Index. décimale : 620 Génie Mécanique Résumé : The present work is a contribution to the study, by numerical simulation, of the characteristics of stationary and transient internal flows of Newtonian fluids and the transport of solid particles occurring in different pipes with singularities. In the first part of this doctoral thesis, the main objective is to analyze the three-dimensional temporal evolution of vortex spatial structures and to highlight the sequence of bifurcation of laminar flow in main and additional counter-rotating cells caused by the duct curvature and for different numbers of Dean. Moreover, with regard to the dynamic and thermal behaviors of the flow, it is the coefficient of friction Cf and the Nusselt number Nu that have been evaluated in order to examine the analogy that may exist between these two parameters along the bent part of the pipe. The effects of the Dean number and the curvature ratio of the pipe are presented and discussed. The second part consists of evaluating, first, the performance of turbulence models based on the RANS approach and bringing to light the adequate numerical model allowing to better simulate the internal flow through square cross-sections curved ducts. The Large Eddy Simulation (LES) approach is then used to simulate the flow of fluid through a 90° bend with a square cross-section for three different Dean numbers in order to explore unsteady turbulent flow phenomena despite its excessive numerical cost. Statistical and filtered parameters characterizing the three-dimensional dynamic and thermal behaviours of the turbulent flow are analysed. Special attention is paid to the effects of secondary flows obtained by the different approaches and the complex unsteady coherent eddy structures captured by the LES approach, on the non-homogeneous distributions of friction and heat transfer on the internal, external and lateral walls of the curved duct. In addition, an additional non-exhaustive study was presented. It deals with the injection of particles. These particles were injected into a curved pipe and the wall erosion rate was evaluated for different Reynolds numbers and particle sizes. Diplôme : Doctorat en sciences En ligne : ../theses/gmecanique/GAC7308.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=10923

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
GAC/7308	GAC/7308	Thèse	Bibliothèque principale	Thèses	Disponible