11 recherche sur le tag 'Nanofluide'   

Contribution à l’etude théorique des fluides caloporteurs tel les nanofluides; / Oussama Benzeggouta  

Public ISBD Titre : Contribution à l’etude théorique des fluides caloporteurs tel les nanofluides; : Comparaison avec les fluides caloporteurs usuels. Type de document : texte imprimé Auteurs : Oussama Benzeggouta, Auteur ; Toufik Boufendi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 127 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD. 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Physique Tags : physique: Energies Renouvelables  Nanofluide  convection forcée et mixte  simulation numérique  conductivité thermique  conduit cylindrique horizontal  Nanofluid  Forced and mixed convection  Numerical simulation  Thermal conductivity  Horizontal pipe  سائل يحتوي جسيمات نانومتريه  حمل قسري وهجين  محاكاة رقمية  ناقلية حرارية  أنبوب أفقي Index. décimale : 530 Physique Résumé : The present work is concerned of numerical simulation of three-dimensional laminar forced and mixed convection of nanofluids. The effects of nanoparticle material, base fluid and volume concentration were highlighted. Al2O3-eau, Cu-eau and Al2O3-eau/ éthylène-glycol nanofluides were employed in this study at multiple volume fractions. The flow geometry is horizontal smooth pipe submitted to a constant and uniform heat flux. Based on single-phase approach, three dimensional conservation equations of mass, momentum and energy with the appropriate boundary conditions have been solved using finite volume method with the schemes of spatial and temporal discretization of second order precision and by using the SIMPLER. At a fixed Reynolds number Re = 300 and Grashof number varying from 0 to 5×105. The results show an increase in heat transfer ratio compared to pure water at several volume fractions for both alumina and copper based nanofluids. At a fixed volume fraction, the axial Nusselt number does not increase significantly in forced convection case. However, in mixed convection case the axial Nusselt number augments considerably especially with Cu-water nanofluid. Instead, the dispersion of the alumina nanoparticles in the water / ethylene glycol mixture with two volume concentrations 30 and 50% gives a better heat transfer ratio compared to pure water base fluid. On the other hand, secondary flow and axial velocity are slightly affected by nanoparticles volume fraction. It is proved in this study that nanofluids can also contributes to optimise pipes compactness, using 2% and 4% of alumina and copper respectively dispersed in water flowing through a pipe with given length gives higher axial Nusselt number ratio compared to pipes larger length but containing pure water. Diplôme : Doctorat En ligne : ../theses/physique/BEN7543.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11383 Contribution à l’etude théorique des fluides caloporteurs tel les nanofluides; : Comparaison avec les fluides caloporteurs usuels. [texte imprimé] / Oussama Benzeggouta, Auteur ; Toufik Boufendi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2019 . - 127 f. ; 30 cm. Doctorat 3éme CYCLE LMD. 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Physique Tags : physique: Energies Renouvelables  Nanofluide  convection forcée et mixte  simulation numérique  conductivité thermique  conduit cylindrique horizontal  Nanofluid  Forced and mixed convection  Numerical simulation  Thermal conductivity  Horizontal pipe  سائل يحتوي جسيمات نانومتريه  حمل قسري وهجين  محاكاة رقمية  ناقلية حرارية  أنبوب أفقي Index. décimale : 530 Physique Résumé : The present work is concerned of numerical simulation of three-dimensional laminar forced and mixed convection of nanofluids. The effects of nanoparticle material, base fluid and volume concentration were highlighted. Al2O3-eau, Cu-eau and Al2O3-eau/ éthylène-glycol nanofluides were employed in this study at multiple volume fractions. The flow geometry is horizontal smooth pipe submitted to a constant and uniform heat flux. Based on single-phase approach, three dimensional conservation equations of mass, momentum and energy with the appropriate boundary conditions have been solved using finite volume method with the schemes of spatial and temporal discretization of second order precision and by using the SIMPLER. At a fixed Reynolds number Re = 300 and Grashof number varying from 0 to 5×105. The results show an increase in heat transfer ratio compared to pure water at several volume fractions for both alumina and copper based nanofluids. At a fixed volume fraction, the axial Nusselt number does not increase significantly in forced convection case. However, in mixed convection case the axial Nusselt number augments considerably especially with Cu-water nanofluid. Instead, the dispersion of the alumina nanoparticles in the water / ethylene glycol mixture with two volume concentrations 30 and 50% gives a better heat transfer ratio compared to pure water base fluid. On the other hand, secondary flow and axial velocity are slightly affected by nanoparticles volume fraction. It is proved in this study that nanofluids can also contributes to optimise pipes compactness, using 2% and 4% of alumina and copper respectively dispersed in water flowing through a pipe with given length gives higher axial Nusselt number ratio compared to pipes larger length but containing pure water. Diplôme : Doctorat En ligne : ../theses/physique/BEN7543.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11383

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Modélisation du transfert thermique par convection naturelle dans les géométries pratiques. / Mabrouk Guestal  

Public ISBD Titre : Modélisation du transfert thermique par convection naturelle dans les géométries pratiques. Type de document : texte imprimé Auteurs : Mabrouk Guestal, Auteur ; Mahfoud Kadja, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 240 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Génie Mécanique Tags : G. Mécanique: Énergétique  Convection naturelle  Convection naturelle tridimensionnelle  Enceinte cylindrique horizontale  Enceinte sphérique  Chauffe-eau solaire  chauffage partiel  volumes finis  Nanofluide  Nanotubes  Natural convection  Three-dimensional natural convection  Horizontal cylindrical enclosure  Spherical enclosure  Solar water heater  partial heating  Finite volume  Nanofluid  Nanotube  الحمل الحراري الطبیعي  الحمل الحراري الطبیعي ثلاثي الأبعاد  حاویة أسطوانیة أفقیة  حاویة كرویة  سخان الماء الشمسي  تسخین جزئي  الحجوم المنتھیة  سوائل النانو  أنابیب النانو Index. décimale : 620 Génie Mécanique Résumé : The objective of this doctoral thesis is to study the thermal and dynamic structures of the flow resulting from natural convection heat transfer within different practical geometries, applying the most recent methods used to improve the heat transfer. For this reason, two studies on this subject have been carried out. In the first study, a numerical study was carried out on heat transfer by natural convection using two nanofluides inside a horizontal cylindrical enclosure with partial heating of its lower part at constant temperature or constant heat flux, the length of the heat source is changed from 5% to 25% of the total perimeter of the enclosure, the rest of the unheated parts of the bottom wall are considered as adiabatic, the two side parts of the enclosure are considered at a low constant temperature, each one of them has a length of 25% of the total perimeter of the enclosure, the top part of the enclosure is considered as adiabatic, it has a length of 25% of the total perimeter. To analyze the effect of using nanofluids with different particles volume fractions on heat transfer inside cylindrical horizontal enclosures, two nanofluids (Cu-water, TiO2-water) were used with volume fraction of nanoparticles being varied in the range of 0 corresponding to pure water) to 0.05. The steady state forms of Navier-Stokes equations and the equations of conservation of mass and energy in twodimensional cylindrical coordinates have been solved by the finite volume method and the SIMPLE algorithm was used for the pressure-velocity coupling. The Rayleigh number was varied in the interval 103 to 106. This research is characterized by a detailed analysis of the effect of changing both the Rayleigh number, the heated length and the value of nanoparticles volume fraction on the dynamic and thermal fields, on the percentage enhancement of the average Nusselt numbers, and also on the variation of the temperature and the vertical velocity component at the vertical and horizontal central lines of the enclosure. The results obtained were summarized in the form of correlation equations of the average Nusselt number as a function of the heated length, the Rayleigh number and volume fraction for both types of nanofluids. In the second study, a numerical study was carried out on the effect of using two techniques for the optimization of heat transfer by natural convection in a three-dimensional spherical enclosure of solar water heater. The outer wall (solar collector) is considered as a heated wall at a constant temperature, the wall which is located behind the solar collector is considered as adiabatic wall. In the enclosure there is a spiral tube, its wall is under a low temperature which increases linearly in terms of enclosure height. The first technique is to exploit nanotechnology using two types of nanofluids Cu-Water and CNT-Water, to improve the heat transfer in the enclosures of spherical solar water heaters, the volume fraction of nanoparticles was varied in the range of 0 (corresponding to pure water) to 0.05. The second technique involves making geometric modifications to the enclosure of spherical solar water heater to improve the natural convection heat transfer, these modifications consist in creating concentric annular orifices in the lower part of the internal adiabatic wall of the solar water heater, the number of annular orifices varies from 1 to 6. The Rayleigh number was varied in the interval 104 to 106. The steady state forms of Navier-Stokes equations and the equations of conservation of mass and energy in three-dimensional spherical coordinates have been solved by the finite volume method. The SIMPLE algorithm was used for the pressure-velocity coupling. This research is characterized by a detailed analysis of the effect of changing both the Rayleigh number, the number of annular orifices and the value of nanoparticles volume fraction on the dynamic and thermal fields and on the heat transfer and its percentage improvement. The results obtained were summarized in the form of correlation equations of the average Nusselt number as a function of the Rayleigh number, the number of annular orifices and the volume fraction of the nanofluid. Through the results obtained in all the studies carried out in the frame of this doctoral thesis, a very important theorem has been reached on the improvement of heat transfer by natural convection in enclosures. The application of this theorem can revolutionize the field of performance improvement of various thermal engineering systems whose operating principle depends on heat transfer by natural convection. Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/gmecanique/GUE7495.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11327 Modélisation du transfert thermique par convection naturelle dans les géométries pratiques. [texte imprimé] / Mabrouk Guestal, Auteur ; Mahfoud Kadja, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 240 f. ; 30 cm. 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Génie Mécanique Tags : G. Mécanique: Énergétique  Convection naturelle  Convection naturelle tridimensionnelle  Enceinte cylindrique horizontale  Enceinte sphérique  Chauffe-eau solaire  chauffage partiel  volumes finis  Nanofluide  Nanotubes  Natural convection  Three-dimensional natural convection  Horizontal cylindrical enclosure  Spherical enclosure  Solar water heater  partial heating  Finite volume  Nanofluid  Nanotube  الحمل الحراري الطبیعي  الحمل الحراري الطبیعي ثلاثي الأبعاد  حاویة أسطوانیة أفقیة  حاویة كرویة  سخان الماء الشمسي  تسخین جزئي  الحجوم المنتھیة  سوائل النانو  أنابیب النانو Index. décimale : 620 Génie Mécanique Résumé : The objective of this doctoral thesis is to study the thermal and dynamic structures of the flow resulting from natural convection heat transfer within different practical geometries, applying the most recent methods used to improve the heat transfer. For this reason, two studies on this subject have been carried out. In the first study, a numerical study was carried out on heat transfer by natural convection using two nanofluides inside a horizontal cylindrical enclosure with partial heating of its lower part at constant temperature or constant heat flux, the length of the heat source is changed from 5% to 25% of the total perimeter of the enclosure, the rest of the unheated parts of the bottom wall are considered as adiabatic, the two side parts of the enclosure are considered at a low constant temperature, each one of them has a length of 25% of the total perimeter of the enclosure, the top part of the enclosure is considered as adiabatic, it has a length of 25% of the total perimeter. To analyze the effect of using nanofluids with different particles volume fractions on heat transfer inside cylindrical horizontal enclosures, two nanofluids (Cu-water, TiO2-water) were used with volume fraction of nanoparticles being varied in the range of 0 corresponding to pure water) to 0.05. The steady state forms of Navier-Stokes equations and the equations of conservation of mass and energy in twodimensional cylindrical coordinates have been solved by the finite volume method and the SIMPLE algorithm was used for the pressure-velocity coupling. The Rayleigh number was varied in the interval 103 to 106. This research is characterized by a detailed analysis of the effect of changing both the Rayleigh number, the heated length and the value of nanoparticles volume fraction on the dynamic and thermal fields, on the percentage enhancement of the average Nusselt numbers, and also on the variation of the temperature and the vertical velocity component at the vertical and horizontal central lines of the enclosure. The results obtained were summarized in the form of correlation equations of the average Nusselt number as a function of the heated length, the Rayleigh number and volume fraction for both types of nanofluids. In the second study, a numerical study was carried out on the effect of using two techniques for the optimization of heat transfer by natural convection in a three-dimensional spherical enclosure of solar water heater. The outer wall (solar collector) is considered as a heated wall at a constant temperature, the wall which is located behind the solar collector is considered as adiabatic wall. In the enclosure there is a spiral tube, its wall is under a low temperature which increases linearly in terms of enclosure height. The first technique is to exploit nanotechnology using two types of nanofluids Cu-Water and CNT-Water, to improve the heat transfer in the enclosures of spherical solar water heaters, the volume fraction of nanoparticles was varied in the range of 0 (corresponding to pure water) to 0.05. The second technique involves making geometric modifications to the enclosure of spherical solar water heater to improve the natural convection heat transfer, these modifications consist in creating concentric annular orifices in the lower part of the internal adiabatic wall of the solar water heater, the number of annular orifices varies from 1 to 6. The Rayleigh number was varied in the interval 104 to 106. The steady state forms of Navier-Stokes equations and the equations of conservation of mass and energy in three-dimensional spherical coordinates have been solved by the finite volume method. The SIMPLE algorithm was used for the pressure-velocity coupling. This research is characterized by a detailed analysis of the effect of changing both the Rayleigh number, the number of annular orifices and the value of nanoparticles volume fraction on the dynamic and thermal fields and on the heat transfer and its percentage improvement. The results obtained were summarized in the form of correlation equations of the average Nusselt number as a function of the Rayleigh number, the number of annular orifices and the volume fraction of the nanofluid. Through the results obtained in all the studies carried out in the frame of this doctoral thesis, a very important theorem has been reached on the improvement of heat transfer by natural convection in enclosures. The application of this theorem can revolutionize the field of performance improvement of various thermal engineering systems whose operating principle depends on heat transfer by natural convection. Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/gmecanique/GUE7495.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11327

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Étude Numérique des écoulements thermoconvectifs d’un nanofluide à travers un espace cylindrique annulaire muni d’ailettes / Mohammed Benkhedda  

Public ISBD Titre : Étude Numérique des écoulements thermoconvectifs d’un nanofluide à travers un espace cylindrique annulaire muni d’ailettes Type de document : texte imprimé Auteurs : Mohammed Benkhedda, Auteur ; Toufik Boufendi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 251 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Chimie Tags : Nanofluide  Convection mixte  Cylindre annulaire horizontal  Monophasique  Ailettes longitudinales  Nanofluide hybride  Volumes finis  Nanofluid  Mixed convection  Horizontal annular cylinder  Single phase  longitudinal fins  Hybrid nanofluid  Finite volume  ائع نانوي  الحمل الحراري مختلطة  اسطوانة حلقية أفقية  أحادي الطور  زعانف طولية  مائع نانوي هجين  الحجوم المنتهية Index. décimale : 530 Physique Résumé : The doctoral project concerns a three-dimensional numerical study of the thermo-convective flows of a nanofluid through an annular cylindrical space without fin and equipped with fins. Newtonian, incompressible and laminar flow with temperature dependent physical properties. The single-phase approach is adopted. The outer cylinder is uniformly heated while the inner cylinder is adiabatic. The flow and thermal fields are modeled by the continuity equation, the three momentum equations and the energy equation of the nanofluid with appropriate initial and boundary conditions using a cylindrical coordinate system. The nonlinear differential equations with partial derivatives are solved numerically by the finite volume method with a spatio-temporal discretization of the second order. The SIMPLER algorithm was used to solve the speed-pressure coupling. A complete parametric analysis on the effect of the presence of nanoparticles dispersed in the fluid such as volume fraction, type and shape on the development of thermal and hydrodynamic fields. The dimensionless control parameters that control the problem under consideration are the Reynolds number, the Prandtl number and the Grashof number, a radius ratio set to 2. For the volume fraction ranging from 0 to 10%, six nanoparticles Types, two metallic types Cu and Ag, three ceramics Al2O3, TiO2 and CuO. Also four forms of the nanoparticles are the shape the spherical shape, Blade, Cylinder, Platelet and Bricks shape. The study of these effects on heat transfer in a annular cylinder without fins and with fins is the main objective of this study. The results concerning the different cases studied for the effect of the volume fraction of the different nanofluids shows that the increase in the volume fraction increases the heat transfer along the annular duct. The axial and mean Nusselt numbers obtained are also higher in the case of the nanofluid (Ag / water). They also show that the use of the Ag nanoparticle induces a better improvement of the heat transfer followed by Cu, Al2O3, CuO at the end TiO2. Regarding the effect of the shape of the nanoparticles Blade shape greatly improves the heat transfer compared to other shapes. A generating correlation expresses the average Nusselt number for the different shapes as a function of the volume fraction proposed: Nu moy = a + bϕ + cϕ2. Another correlation which expresses the average Nusselt number of the nanofluid (TiO2/water) and the hybrid nanofluid (Ag-TiO2 / water) as a function of the number of Grashof, Prandtl and the volume fraction: The use of the heat-generating fins, attached longitudinally to the outer cylinder and immersed in the nanofluid, greatly improves the heat transfer compared to those of a nonfinned horizontal duct dû to the increase in the exchange area between The nanofluid and the fins in the annular space. Diplôme : Doctorat en sciences En ligne : ../theses/physique/BOU7334.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=10984 Étude Numérique des écoulements thermoconvectifs d’un nanofluide à travers un espace cylindrique annulaire muni d’ailettes [texte imprimé] / Mohammed Benkhedda, Auteur ; Toufik Boufendi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 251 f. ; 30 cm. 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Chimie Tags : Nanofluide  Convection mixte  Cylindre annulaire horizontal  Monophasique  Ailettes longitudinales  Nanofluide hybride  Volumes finis  Nanofluid  Mixed convection  Horizontal annular cylinder  Single phase  longitudinal fins  Hybrid nanofluid  Finite volume  ائع نانوي  الحمل الحراري مختلطة  اسطوانة حلقية أفقية  أحادي الطور  زعانف طولية  مائع نانوي هجين  الحجوم المنتهية Index. décimale : 530 Physique Résumé : The doctoral project concerns a three-dimensional numerical study of the thermo-convective flows of a nanofluid through an annular cylindrical space without fin and equipped with fins. Newtonian, incompressible and laminar flow with temperature dependent physical properties. The single-phase approach is adopted. The outer cylinder is uniformly heated while the inner cylinder is adiabatic. The flow and thermal fields are modeled by the continuity equation, the three momentum equations and the energy equation of the nanofluid with appropriate initial and boundary conditions using a cylindrical coordinate system. The nonlinear differential equations with partial derivatives are solved numerically by the finite volume method with a spatio-temporal discretization of the second order. The SIMPLER algorithm was used to solve the speed-pressure coupling. A complete parametric analysis on the effect of the presence of nanoparticles dispersed in the fluid such as volume fraction, type and shape on the development of thermal and hydrodynamic fields. The dimensionless control parameters that control the problem under consideration are the Reynolds number, the Prandtl number and the Grashof number, a radius ratio set to 2. For the volume fraction ranging from 0 to 10%, six nanoparticles Types, two metallic types Cu and Ag, three ceramics Al2O3, TiO2 and CuO. Also four forms of the nanoparticles are the shape the spherical shape, Blade, Cylinder, Platelet and Bricks shape. The study of these effects on heat transfer in a annular cylinder without fins and with fins is the main objective of this study. The results concerning the different cases studied for the effect of the volume fraction of the different nanofluids shows that the increase in the volume fraction increases the heat transfer along the annular duct. The axial and mean Nusselt numbers obtained are also higher in the case of the nanofluid (Ag / water). They also show that the use of the Ag nanoparticle induces a better improvement of the heat transfer followed by Cu, Al2O3, CuO at the end TiO2. Regarding the effect of the shape of the nanoparticles Blade shape greatly improves the heat transfer compared to other shapes. A generating correlation expresses the average Nusselt number for the different shapes as a function of the volume fraction proposed: Nu moy = a + bϕ + cϕ2. Another correlation which expresses the average Nusselt number of the nanofluid (TiO2/water) and the hybrid nanofluid (Ag-TiO2 / water) as a function of the number of Grashof, Prandtl and the volume fraction: The use of the heat-generating fins, attached longitudinally to the outer cylinder and immersed in the nanofluid, greatly improves the heat transfer compared to those of a nonfinned horizontal duct dû to the increase in the exchange area between The nanofluid and the fins in the annular space. Diplôme : Doctorat en sciences En ligne : ../theses/physique/BOU7334.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=10984

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Contribution à l’intensification des transferts thermiques par un nanofluide dans un échangeur thermique à tube elliptique coaxial. / Abdeslem Bouzerzour  

Public ISBD Titre : Contribution à l’intensification des transferts thermiques par un nanofluide dans un échangeur thermique à tube elliptique coaxial. Type de document : texte imprimé Auteurs : Abdeslem Bouzerzour, Auteur ; Mahfoud Djezzar, Directeur de thèse Mention d'édition : 20/10/2020 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 79 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD. 1 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Physique Tags : physique: Energies Renouvelables  Transferts de chaleur  Convection naturelle  Espace annulaire elliptique  Formulation vorticité-fonction de courant  nanofluide  chauffage partiel  Heat transfers  Natural convection  Elliptical annular space  Vorticity-Stream function formulation  nanofluid  partial heating  نقل الحرارة  الحمل الحراري الطبيعي  الحيز الحلقي الإهليليجي  صياغة التدويم-دالة التيار  مائع نانومتري  التسخين الجزئي Index. décimale : 530 Physique Résumé : The author presents here, a contribution to the study of two-dimensional laminar natural convection of Newtonian incompressible nanofluids confined in coaxial elliptical tubes heat exchanger. The external wall is maintained cold while the internal wall is subjected to different parietal thermal conditions. The effects of inclination angle and the injected nanoparticles type are examined for considered, Rayleigh number and volume fraction, values. A numerical code with finite volumes method based on Vorticity-Stream function formulation is developed to resolve the continuity, momentum, and energy equations written in elliptic coordinates considering Boussinesq approximation. The study consists of three parts, for different Rayleigh numbers (103 Diplôme : Doctorat En ligne : ../theses/physique/BOU7655.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11489 Contribution à l’intensification des transferts thermiques par un nanofluide dans un échangeur thermique à tube elliptique coaxial. [texte imprimé] / Abdeslem Bouzerzour, Auteur ; Mahfoud Djezzar, Directeur de thèse  . -  20/10/2020 . - جامعة الإخوة منتوري قسنطينة, 2020 . - 79 f. ; 30 cm. Doctorat 3éme CYCLE LMD. 1 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Physique Tags : physique: Energies Renouvelables  Transferts de chaleur  Convection naturelle  Espace annulaire elliptique  Formulation vorticité-fonction de courant  nanofluide  chauffage partiel  Heat transfers  Natural convection  Elliptical annular space  Vorticity-Stream function formulation  nanofluid  partial heating  نقل الحرارة  الحمل الحراري الطبيعي  الحيز الحلقي الإهليليجي  صياغة التدويم-دالة التيار  مائع نانومتري  التسخين الجزئي Index. décimale : 530 Physique Résumé : The author presents here, a contribution to the study of two-dimensional laminar natural convection of Newtonian incompressible nanofluids confined in coaxial elliptical tubes heat exchanger. The external wall is maintained cold while the internal wall is subjected to different parietal thermal conditions. The effects of inclination angle and the injected nanoparticles type are examined for considered, Rayleigh number and volume fraction, values. A numerical code with finite volumes method based on Vorticity-Stream function formulation is developed to resolve the continuity, momentum, and energy equations written in elliptic coordinates considering Boussinesq approximation. The study consists of three parts, for different Rayleigh numbers (103 Diplôme : Doctorat En ligne : ../theses/physique/BOU7655.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11489

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BOU/7655	BOU/7655	Thèse	Bibliothèque principale	Thèses	Disponible

Intensification des transferts thermiques en convection forcée par l'utilisation d'une nouvelle classe de fluides porteurs dans une conduite cylindrique. / Ammar Maouassi  

Public ISBD Titre : Intensification des transferts thermiques en convection forcée par l'utilisation d'une nouvelle classe de fluides porteurs dans une conduite cylindrique. Type de document : texte imprimé Auteurs : Ammar Maouassi, Auteur ; Abdelhadi Beghidja, Directeur de thèse Mention d'édition : 20/11/2019 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 210 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Génie Mécanique Tags : G.Mécanique: Energétique  Nanofluide  Nanoparticule  Echangeur  Capteur solaire plan  Al2O3  CuO  SiO2  TiO2  نانوفلويد  الجزيئات النانومترية  مبادل حراري  لوح تجميع الطاقة الشمسية المسطح Index. décimale : 620 Génie Mécanique Résumé : Numerical studies of laminar and turbulent forced convection, permanent and stationary through a cylindrical pipe for the case of a heat exchanger and the case of a flat plat solar collector, the calculations are performed for the case of water and nanofluides of metal oxides (Al2O3, CuO, SiO2, TiO2).The fluids are supposed Newtonian. The heat transfer equations governing have been resolved, by the use of finite volume method to discretize the mathematical model equations (continuity, momentum and energy equations). Dynamic and thermal fields are obtained for different values of the Reynolds number ranging from 25 to 900 and for different nanoparticles concentration of (1%, 2%, 3%, 5% and 10%).Analyses of temperature, pressure drop coefficient and the calculation Nusselt number has been realized. The results obtained show that heat transfer is better if we increased the nanoparticles concentration and the Reynolds number, and found that the best transfer fluid is the nanofluid contains nanoparticles of Al2O3followed by CuO and TiO2, and finally SiO2, and an increase of Al2O3 concentration intensifies the heat transfer coefficient without affecting the pressure drop, and another the power dissipated by the fluid transport. Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/gmecanique/MAO7598.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11434 Intensification des transferts thermiques en convection forcée par l'utilisation d'une nouvelle classe de fluides porteurs dans une conduite cylindrique. [texte imprimé] / Ammar Maouassi, Auteur ; Abdelhadi Beghidja, Directeur de thèse  . -  20/11/2019 . - جامعة الإخوة منتوري قسنطينة, 2019 . - 210 f. ; 30 cm. 1 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais Génie Mécanique Tags : G.Mécanique: Energétique  Nanofluide  Nanoparticule  Echangeur  Capteur solaire plan  Al2O3  CuO  SiO2  TiO2  نانوفلويد  الجزيئات النانومترية  مبادل حراري  لوح تجميع الطاقة الشمسية المسطح Index. décimale : 620 Génie Mécanique Résumé : Numerical studies of laminar and turbulent forced convection, permanent and stationary through a cylindrical pipe for the case of a heat exchanger and the case of a flat plat solar collector, the calculations are performed for the case of water and nanofluides of metal oxides (Al2O3, CuO, SiO2, TiO2).The fluids are supposed Newtonian. The heat transfer equations governing have been resolved, by the use of finite volume method to discretize the mathematical model equations (continuity, momentum and energy equations). Dynamic and thermal fields are obtained for different values of the Reynolds number ranging from 25 to 900 and for different nanoparticles concentration of (1%, 2%, 3%, 5% and 10%).Analyses of temperature, pressure drop coefficient and the calculation Nusselt number has been realized. The results obtained show that heat transfer is better if we increased the nanoparticles concentration and the Reynolds number, and found that the best transfer fluid is the nanofluid contains nanoparticles of Al2O3followed by CuO and TiO2, and finally SiO2, and an increase of Al2O3 concentration intensifies the heat transfer coefficient without affecting the pressure drop, and another the power dissipated by the fluid transport. Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/gmecanique/MAO7598.pdf Format de la ressource électronique : pdf Permalink : index.php?lvl=notice_display&id=11434

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
MAO/7598	MAO/7598	Thèse	Bibliothèque principale	Thèses	Disponible

Etude de la convection mixte dans des cavités. / Ilhem Zeghbid  

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Étude Numérique de la Convection Mixte dans un Canal Horizontal Contenant des Ailettes / Moussa Khentoul  

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Génération d’entropie due au refroidissement par convection naturelle d’un nanofluide / Abd el malik Bouchoucha  

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Contribution à l’étude de la convection naturelle instationnaire dans des enceintes cubiques inclinées. / Khadoudja Azzouz  

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Etude numérique des transferts thermiques convectifs avec nano-fluides. / Esma Belahmadi  

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Etude paramétrique des échanges convectifs turbulents dans les configurations d’intérêt pratique / Ridha Mebrouk  

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