M. BENDERRADJI Razik

A numerical study was conducted to investigate mixed convection in a square ventilated cavity
with a central cooling cylinder, aimed at evaluating heat exchange. The study used pure water and mixtures
with Cu and Al₂O₃ nanoparticles. The analysis covered a wide range of Richardson numbers (0.1 < Ri <
100), Hartmann numbers (0 < Ha < 100), and nanoparticle volume fractions (0% < φ < 8%), under the
influence of a uniform external magnetic field. The governing non-dimensional equations and boundary
conditions were solved using the finite volume method and the SIMPLER algorithm.

FSW is a welding method that joins pieces of material by rotating a non-consumable pin at
high speeds (RPM) while moving it along the weld joint. The combination of this rotation
and movement generates heat through friction between the tool and the sheets, facilitating
the welding process without the requirement for filler metal. Developed by the British
Welding Institute (TWI) in 1991, FSW is celebrated for producing strong, reliable welds and
is extensively used in industries such as automotive and aerospace. In these sectors,
Brazilian Journal of Technology 2
ISSN: 2595-5748
Brazilian Journal of Technology, Curitiba, v.7, n.4, p. 01-22, 2024
aluminum alloys are essential due to their unique set of properties, making them highly
suitable for FSW applications. In FSW, welding speed refers to the linear velocity at which
the tool progresses along the joint line during the welding process. This parameter plays a
pivotal role in controlling heat generation, material flow, and ultimately, the quality of the
weld. The quantity of heat introduced to the plates directly influences the final weld quality,
as well as the residual stresses and deformation observed in the workpieces. This research
examines how different welding speeds affect temperature distribution, the width of the heataffected zone, and the Von Mises stress distribution in welded aluminum alloy 6061 sheets.
The aim of this study is to gain a comprehensive understanding of how these factors interact,
with the ultimate goal of contributing to the optimization of FSW parameters and improving
weld quality. The analysis was performed using finite element method and ALTAIR
software, providing valuable insight into the effects of welding speed variations.

non abstract

L3 : Physique Énergétique et Énergies Renouvelables

polycopie de cours pour les Master I et L3 : Physique Énergétique et Énergies Renouvelables

The turbulent flow within Over-Expanded Nozzles is characterized by shock waves inducing
unsteady separation of the boundary layer, which can exhibit both free and restricted detachment. This study
investigates various physical phenomena encountered during the expansion regime, including supersonic jet
formation, jet separation, adverse pressure gradients, shockwave interactions, turbulent boundary layers,
compressible mixture layers, and large-scale turbulence. These complex phenomena significantly influence
nozzle performance. Utilizing numerical simulations based on the resolution of Navier-Stokes equations via
finite volume methods and employing the CFD-FASTRAN code, this research analyzes detachment
characteristics, transition phenomena, and the predictive accuracy of different turbulence models. A test case
from the ATAC project CNES-ONERA (Aerodynamics of Hoses and Back-bodies), is examined to elucidate
the hysteresis phenomenon and asymmetrical configurations resulting from boundary layer detachment.

non abstract

This study presents a parametric numerical investigation of laminar natural convection and heat transfer in a cavity
with opposite sinusoidal wavy walls, filled with hybrid Ag-CuO/water nanofluid. The vertical walls of the cavity are
maintained at distinct hot and cold temperatures, while the upper and lower boundaries are thermally insulated. The
study examines the effects of key factors, including the sinusoidal wall shape, nanoparticle volume fractions (0% ≤ 𝜙 ≤
6%), and Rayleigh numbers (10³ ≤ Ra ≤ 10⁶). A finite volume discretization method, using the SIMPLE algorithm, is
employed to solve the governing equations, with Ansys Fluent software ensuring quadratic accuracy. Mesh
independence is confirmed with a 200 × 200 mesh, and code validation is performed through comparison with previous
studies. Results indicate that increasing the nanoparticle volume fraction enhances heat transfer within the cavity.
Additionally, the Rayleigh number significantly influences the heat transfer mode, with higher Ra values promoting
stronger convective activity. Detailed analysis of temperature and velocity profiles, along with Nusselt number
variations, highlights the impact of nanoparticle concentrations and Rayleigh numbers. The wavy wall geometry
improves fluid mixing and thermal boundary layer interaction, leading to enhanced heat dissipation. These findings
underscore the potential of hybrid nanofluids and wavy wall designs to optimize heat transfer in engineering systems.

In this numerical study, the focus was on analyzing the heat transfer by mixed convection in a
ventilated cavity filled with a hybrid nano-fluid. The hybrid nano-fluid consists of nano-particles (copper
(Cu) and alumina (Al2O3)) dispersed in a base fluid (water). The volume fraction of nano-particles is 4 %.
The cavity housed a cold cylinder at its center and incorporated two gates (orifices) for the influx and
efflux of the flow., with a fixed Reynolds number (Re) and varying Richardson numbers (Ri) set at 0.1, 1,
10, and 100. The cavity was subjected to isothermal heating by a heat source on the lower wall to
maintain a constant temperature, while the remaining walls were kept adiabatic. The ventilated cavity is
subjected to mixed convection, where both natural convection and forced convection effects are
considered. The governing equations for the stationary laminar flow were solved numerically using the
finite volume method. The numerical results revealed the significant impact of Ri on heat transfer within
the ventilated cavity. Consequently, the heat transfer rate (expressed by Nusselt number Nu) demonstrated
an upward trend with increasing Ri values. Overall, the results of this study were provide valuable insights
for understanding the behavior and performance of systems that utilize hybrid nano-fluids in applications
such as microelectronics cooling, heat exchangers, and energy storage devices.

In contemporary power engineering and microelectronics, the efciency of cooling systems is of crucial importance. To
meet this requirement, specialized approaches and the use of nanofuids are employed to improve the heat dissipation of
heat-generating components. This study presents a methodology based on a numerical simulation investigation and statistical
analysis using the Response Surface Methodology (RSM) to estimate the average Nusselt number (Nuavg) associated with
mixed convection in a ventilated cavity. The study considered pure water and mixtures of nanoparticles (Cu, Ag, and TiO2) as
heat transfer fuids, exploring various values of the Richardson number (0.1 to 100) and volume fractions (0 to 8%). Analysis
of Variance (ANOVA) and the quadratic mathematical model developed by RSM efectively predicted the results of the
numerical simulation with a coefcient of determination R2
close to 1. The results obtained from the 3D curves of the RSM
show that the average Nusselt number (Nuavg) increases signifcantly with the Richardson number. Conversely, an increase
in the volumetric fraction leads to a slight decrease in Nuavg. Furthermore, it is observed that the agent (Ag) generates higher
Nuavg values compared to other materials such as copper (Cu) and TiO2. Combining the RSM method with the desirability
function (DF) allows for achieving the optimal average Nusselt number (Nuavg). Validation of the values proposed by the
DF and those obtained by simulation shows a very small relative error, less than 0.13%.

This research presents the results of a numerical study on mixed convection in a ventilated cavity
with a central cold block of varying shapes. The direction of the forced flow of Ag/water nanofluid is
perpendicular to the transverse axis (y) of the central cold block. Mixed convection is induced by cooling at the
entrance of the ventilated cavity and uniformly heating its bottom wall. The governing equations for the flow of
an incompressible Newtonian nanofluid are assumed to be two-dimensional, steady, and laminar. The finite
volume method is employed for numerical simulations. A series of calculations are conducted to investigate the
effects of key influencing factors: Reynolds number (Re = 100), Richardson number (Ri = 1), and nanoparticle
volume fractions (0 ≤ ∅ ≤ 8%) on the enhancement of heat transfer. The impact of four different geometric
shapes of the cold obstacle (circular, square, triangular, and elliptical) on fluid flow and heat transfer rate is also
explored. The results indicate that an increase in nanoparticle volume fraction enhances the heat exchange rate
in the cavity only when the geometric shape of the cold obstacle is circular. This is followed by square and
triangular shapes, which approximately yield concordant results, and then the elliptical shape.

A parametric numerical study is conducted on laminar natural convection and heat transfer in a cavity with opposing undulated walls saturated with a hybrid Ag-CuO/water nanofluid. The two vertical walls of the sinusoidally undulated cavity are maintained at hot and cold temperatures, while the upper and lower walls are thermally insulated. The investigation examines the effects of relevant parameters such as the sinusoidally undulated geometry of the walls for different volumetric fractions of nanoparticles (0% ≤𝝋≤6%) and Rayleigh numbers (103 ≤ Ra ≤ 106) Thefinite-volumee discretization method is employed to solve the system of governing equations. The results indicate that an increase in the volumetric fraction of nanoparticles enhances the heat exchange rate in the cavity. Additionally, the Rayleigh number, with a significant increase in surface area, strongly influences the dominant heat transfer mode in the cavity. Furthermore, an increase in the number of wall undulations leads to a reduction in the heat transferrate. Type or paste your abstract here as prescribed by the journal’s instructions for authors. Type or paste your abstract here as prescribed by the journal’s instructions for authors. Type or paste your abstract here.

Bienvenue dans ce polycopié de cours sur les transferts thermiques et les travaux pratiques associés. Ce document a été conçu pour accompagner votre apprentissage dans le domaine fascinant et crucial du transfert de chaleur. Il vise à fournir une base solide de connaissances théoriques ainsi que des applications pratiques pour renforcer votre compréhension.
Objectifs du Polycopié:
1. Compréhension Théorique : Ce polycopié présente les concepts fondamentaux du transfert de chaleur, couvrant les modes de conduction, convection et rayonnement. Les principes théoriques sont expliqués de manière claire et concise pour faciliter votre compréhension.
2. Applications Pratiques : Les travaux pratiques inclus dans ce document offrent l'opportunité d'appliquer les connaissances théoriques à des situations réelles. Ces exercices visent à renforcer vos compétences pratiques dans l'analyse et la résolution de problèmes liés au transfert de chaleur.
3. Guides d'Étude : Vous trouverez des directives et des conseils pour maximiser votre apprentissage. Les travaux pratiques sont accompagnés d'instructions détaillées pour vous guider tout au long du processus.

This study numerically examines laminar natural convection in a sinusoidal wavy cavity, filled with pure water and Ag-CuO/Water hybrid nanofluid, which is a new advanced nanofluid with two types of nanoparticle materials. The two vertical walls of the enclosure with a sinusoidal undulating geometry are maintained at hot and cold temperatures respectively, while the upper and lower walls are thermally insulated. The present investigation examined the effects of relevant parameters such as sinusoidal wavy wall geometry, for different nanoparticle volume fractions (0% volume concentration ≤𝜙≤6%) and Rayleigh numbers (103 ≤ Ra ≤ 106). The finite volume discretization method is used to solve all the governing equations. The results show that the heat transfer rate inside the corrugated enclosure increases by decreasing the amplitude of the corrugated surface. Additionally, increasing the number of corrugations leads to improving the heat transfer rate. It is also found that by increasing the volume fraction of nanoparticles and the Rayleigh number, the heat transfer rate increases.

The present study is concerned with both the development of the supersonicflow turbulent boundary layer on a flat plate, the distance required to invade the entiresection of the plate, and the effects of the size of the zone of interaction on thedevelopment of the same boundary layer. The increase in the force of the interaction is anincrease in the size of the zones of interactions leading to the formation of a recirculatingbubble which is an area of sign ificant pressure drops. For th is reason, one can decreaseand then increase the Mach number to see a Mach reflection that explains the impact ofthe strong incident shock wave with the boundar y layer. The increase and decrease of theMach number caused the occurrence of a transition in regular reflection (RR)interactions, Mach reflection (MR), which is represented by the iso contours of the fieldsof density. These studies are well in agreement with the trial which was presented byDélery et al. (2009). Another contribution and investigations of the phenomenon of shockwave / turbulent boundary layer interaction were given. The model used in this study isthe kw-SST model, considered to be the mo st suitable for this kind of problem, withspecial treatment of the zone near the wa ll. Numerical simulations were made usingFLUENT software.

(25) (PDF) Etude numérique de transition RR / MR dans l’interaction onde de choc / choc de compression. Available from: https://www.researchgate.net/publication/376328701_Etude_numerique_de_transition_RR_MR_dans_l'interaction_onde_de_choc_choc_de_compression#fullTextFileContent [accessed Jan 28 2024].

This study numerically investigates laminar natural convection in a sinusoidal corrugated cavity, filled with pure water and Ag-CuO/Water hybrid nanofluid, which is a new advanced nanofluid with two types of nanoparticulate materials. In this work, the two vertical walls of the enclosure with a sinusoidal undulating geometry are maintained at hot and cold temperatures respectively, while the upper and lower walls are thermally insulated. The present investigation examined the effects of relevant parameters such as the sinusoidal undulating geometry of the walls, for different volume fractions of nanoparticles (0% volume concentration ≤𝜙≤6%) and Rayleigh numbers (103 ≤ Ra ≤ 106). The finite volume discretization method is used to solve the set of governing equations. The results show that the rate of heat transfer inside the corrugated enclosure increases by decreasing the amplitude of the corrugated surface. In addition, increasing the number of corrugations leads to improved heat transfer rate. It is also found that by increasing the volume fraction of the nanoparticles and the Rayleigh number, the rate of heat transfer increases.

La mécanique des fluides numérique (MFN), plus souvent désignée par le terme anglais computational fluid dynamics (CFD), consiste à étudier les mouvements d'un fluide, ou leurs effets, par la résolution numérique des équations régissant le fluide. En fonction des approximations choisies, qui sont en général le résultat d'un compromis en termes de besoins de représentation physique par rapport aux ressources de calcul ou de modélisation disponibles, les équations résolues peuvent être les équations d'Euler, les équations de Navier-Stokes, etc.

In this work, we carried out a numerical study of the stationary laminar flow by mixed convection in a ventilated two-dimensional cavity containing a cold cylinder in the center of the latter. The cavity is filled with different hybrid nano-fluids, (Water/Ag-TiO2) and (Water/Al2O3-TiO2)). The cavity containing two gates (Orifices) of entry and exit of the flow, for a Reynolds number (Re) fixed so that the Richardson number takes the values: Ri = 0.1, 1, 10 and 100, and a volume fraction of the nanoparticles comprised between (0% and 8%). The square cavity is heated isothermally by the surface of the lower wall by a heat source (The source is to maintain the lower wall at constant temperature), the other walls are maintained adiabatic. The equations, which govern the flow, have been solved numerically using the finite volume method. The results obtained show that the heat transfer increases with the increase in the volume fraction and the Richardson number. Thus the heat transfer rate (Nu) increases with the increase in Ri.

In this work, we carried out a numerical study of the stationary laminar flow by mixed convection in a ventilated two-dimensional cavity containing a cold cylinder in the center of the latter. The cavity is filled with different hybrid nano-fluids, (Water/Ag-TiO2) and (Water/Al2O3-TiO2)). The cavity containing two gates (Orifices) of entry and exit of the flow, for a Reynolds number (Re) fixed so that the Richardson number takes the values: Ri = 0.1, 1, 10 and 100, and a volume fraction of the nanoparticles comprised between (0% and 8%). The square cavity is heated isothermally by the surface of the lower wall by a heat source (The source is to maintain the lower wall at constant temperature), the other walls are maintained adiabatic. The equations, which govern the flow, have been solved numerically using the finite volume method. The results obtained show that the heat transfer increases with the increase in the volume fraction and the Richardson number. Thus the heat transfer rate (Nu) increases with the increase in Ri.

In this work, a numerical study of stationary laminar mixed convection in a ventilated square cavity has been presented. The cavity is filled with different nanofluids and contains two gates (ports) to enter and exit the flow. The straight vertical wall is maintained at a warm temperature, while the other walls are considered adiabatic. The equations governing flow and heat transfer have been solved by the finite volume method using a second-order centered Upwind scheme. Numerical simulations are carried out in the case of pure water fluid, and mixtures of this basic fluid and nanoparticles (Ag and Cu), for a number of Ri varying from (0.04 to 4) and a volume fraction of the nanoparticles between (0% and 10%). The study presented in this work is devoted to a dynamic study in which the Grashof number is fixed at 104, and the Reynolds number is varied. The numerical results obtained show that the heat transfer increases with the increase in the volume fraction also that the enhancement of the product of entropy generation and heat transfer increases considerably with the increase in the Reynolds number. The most effective nanoparticles for increasing the heat exchange rate are Ag. The latter are characterized by a large local Nusselt number, that is to say a very good heat transfer compared to that of metallic Cu nanoparticles.

A numerical simulation of stationary laminar flow by free convection in a two-dimensional cavity filled with different nanofluids (nanofluids and hybrid nanofluids) has been carried out. The square cavity is isothermally heated from below. Indeed, 1/3 of the surface of the lower wall is heated by a heat source (the source is to maintain the lower wall at a constant temperature), the two vertical side walls are cooled and the upper wall is maintained adiabatic. The equations that govern the flow have been solved numerically via the finite volume method using a Power-Low scheme. Numerical simulations are carried out in the case of pure water fluid, and mixtures of this basic fluid and nanoparticles (Ag), (Cu) and hybrid nanoparticle (Ag-CuO), for a Rayleigh number varying from 103 to 105, and a volume fraction of the nanoparticles of between (0% and %4). To deeply examine the effects of relevant parameters on hydrodynamic flow and heat transfer in our setup. The results obtained show that the heat transfer increases with increasing volume fraction and Rayleigh number. Thus the heat transfer rate (Nu) increases with increasing Ra. We will divide this study into two main parts:
• Effect of concentration of nanoparticles.
• Effect of types of nanoparticles.

In this work, a numerical study of stationary laminar mixed convection in a ventilated square cavity has been presented. The cavity is filled with different nanofluids and contains two gates (ports) to enter and exit the flow. The straight vertical wall is maintained at a warm temperature, while the other walls are considered adiabatic. The equations governing flow and heat transfer have been solved by the finite volume method using a second-order centered Upwind scheme. Numerical simulations are carried out in the case of pure water fluid, and mixtures of this basic fluid and nanoparticles (Ag and Cu), for a number of Ri varying from (0.04 to 4) and a volume fraction of the nanoparticles between (0% and 10%). The study presented in this work is devoted to a dynamic study in which the Grashof number is fixed at 104, and the Reynolds number is varied. The numerical results obtained show that the heat transfer increases with the increase in the volume fraction also that the enhancement of the product of entropy generation and heat transfer increases considerably with the increase in the Reynolds number. The most effective nanoparticles for increasing the heat exchange rate are Ag. The latter are characterized by a large local Nusselt number, that is to say a very good heat transfer compared to that of metallic Cu nanoparticles.

L’échange de chaleur par convection mixte dans une cavité 2D d’un écoulement incompressible laminaire, est étudié
numériquement. Cette étude a permis de prédire le comportement de la structure de l’écoulement entre une structure
multicellulaire dominé par une convection naturelle lorsque le nombre de Reynolds est faible, et une structure
multicellulaire dominé par une convection forcée lorsque le nombre de Reynolds est élevé. En premier lieu on fait fixer
le nombre de Grashof pour le nombre de Reynolds variable. En deuxième lieu on fait varier le nombre de Grashof pour
lesquels le nombre de Reynolds est maintenu fixe. Les résultats obtenus donnent une claire comparaison avec ceux trouvés
dans la littérature.

L’utilisation de l’énergie solaire à travers un collecteur parabolique (concentrateur solaire parabolique) promet une
énergie verte limitée telle que la production électrique. Une étude du capteur parabolique solaire a été réalisée sur la
géométrie et la distribution des flux dans la région focale. Le diamètre de la parabole est un paramètre important pour
déterminer le diamètre d'imagerie et non imageur du rayonnement de flux au point focal.
La géométrie a été simulée à l'aide d’un logiciel open source (Tonatiuh) qui permet de modéliser une antenne parabolique
et de simuler son comportement optique. La distribution du flux a ensuite été tabulée sur le graphique coordonné pour
obtenir le diamètre. Les diamètres d'imagerie se situent entre 4 m et plus, tandis que les valeurs de diamètre sans formation
d'image se situent entre 1 et 3 m. Cela montre que le paramètre optimal de la parabole est important pour obtenir une
haute intensité de mise au point.

The flow in an Over-Expanded Nozzle is subjected to shock waves leading to the unsteady separation of the boundary layer. Free detachment may be followed by a restricted detachment. During the expansion regime in propellant nozzles, several physical phenomena are encountered: supersonic jet, jet separation, adverse pressure gradient, shock wave, turbulent boundary layer, highly compressible mixture layer, return flow, large scale turbulence. These very complex phenomena can considerably affect the performance of the nozzle.The numerical investigation was performed by the CFD-FASTRAN search code, using the k-w SST model as the turbulence model. The calculation is performed by solving the Navier-Stokes equations of two-dimensional compressible turbulent flow. It is based on the study of the fluidic vectorization phenomenon of the thrust of a double-injection convergent-divergent supersonic conical nozzle. The study is based on the effect of the ratio of NPR pressures with SPR = 1 on the overall structure of shock waves. The calculation is highlighting the behavior of a flow that has not neglected. In particular, the appearance of the separation zone formed by the fluid jet and the deflection of the main jet cause separation shocks.

Les transferts thermiques sont une science clé de l’énergie. On appelle chaleur l'échange d'énergie qu'il faut ajouter au travail reçu pour obtenir l'échange total d’énergie, et encore « la chaleur, comme le travail, n'est pas une énergie mais un transfert d'énergie ». Destiné en priorité aux étudiants en LMD et aux élèves ingénieurs, ce polycopié aborde les principaux modes de transferts d’énergie: la conduction, le rayonnement et la convection.

Ces phénomènes très différents, mais pouvant interagir, doivent être connus de l’étudiant qui sera confronté un jour ou l’autre à un problème de transfert thermique. Il trouvera dans cette polycopie de nombreuses applications concrètes. Dans ce polycopié, la priorité est donnée à la compréhension physique des phénomènes et à l’apprentissage de la modélisation physique.

Le but de ces travaux pratiques est d’illustrer une partie de ce que vous voyez dans le cours de transfert thermique, d’une part. D’autre part, ces travaux pratiques permettent de vous familiariser avec les méthodes de mesures et de détermination des différents coefficients de transfert thermique.

Enfin, le travail demandé va vous incitera à dépouiller et analyser des données expérimentales, à discuter les résultats obtenus et à rédiger des comptes rendus techniques. Ces trois activités forment l’essentiel de ce que la majorité des étudiants sont appelés à faire le long de leurs carrières. Les comptes rendus sont le véhicule de transmission de vos réflexions, observations et solutions. Votre capacité à composer des rapports clairs et concis augmentera votre crédibilité et propulsera votre réussite. En effet, les résultats les plus intéressants ne peuvent intéresser le lecteur (votre patron ou votre client) que lorsque celui-ci arrive à saisir ce que vous lui présentez, sans s’ennuyer et abandonner la lecture. La capacité de préparer de bons comptes rendus s’apprend par la pratique. C’est la raison pour la quelle on exige un compte rendu bien rédigé.
Dans tout travail expérimental, vous devez estimer l’incertitude des paramètres mesurés ou calculés à partir de mesures directes.
Le polycopié est structuré en cinq TP.
Dans la première partie, nous présenterons tout d’abord des généralités sur le transfert thermique, et quelques notions de base de calcul. La seconde partie présente les cinq travaux pratique, en détails de chacune.

Flow around a finite end cylinder mounted vertically on a flat plate and thermally heated is
simulated numerically by the Large-Scale Simulation (LES) approach. The flow is in subcritical regime
circulate with a velocity U∞=0.54m/s corresponding a Reynolds number ReD=2.2x104
. The boundary
condition of Neumann is imposed on the surface of the cylinder, which is reflected by a density of the heat flux
is = 600W/m2
, for an aspect ratio H/D=5.This simulation induces a complex structure of the flow behind the
cylinder, in particular the appearance of vortices and recirculation zones ahead and behind it. The results
obtained give a clear comparison with those found experimentally and numerically of Guillermo PalauSalvador et al. [2], that were carried out its work in the case of adiabatic flow.

This study provides a 3D numerical simulation of two-phase flow in upward vertical
annuli pipe using the Fluent CFD commercial code. The condition of two-phase flow
was simulated with the Volume of Fluid (VOF) model, taking into consideration
turbulence effects using the k-e model. The internal and external diameters of the pipe
are DT=12.7 mm, DC=38.1 mm, respectively and length L=16 m. Numerical results were
obtained for various values of air velocity, Ug at fixed water velocity (Ul =0.14 m/s). In
this numerical simulation, we have identified global flux structures and their transition
regimes, such as the size and shape of bubbles, slug and their zigzag and coalescence
phenomena. These flow regimes have been clearly influenced by the air velocity. The
results obtained have been validated and are consistent with those experimentally
reported

Envisager de rendre compte de l’ensemble des réalités de la construction mécanique du XXIe, c’est considérer d’emblée le caractère industriel d’une activité incluant les technologies les plus diverses, de l'électricité à l'informatique, et recouvrant les besoins de la construction de véhicules terrestres, aériens, spatiaux, ainsi que les machines permettant de construire ces machines. Cependant, la construction mécanique reste au cœur de l’industrie, tant d’un point de vue historique (jusqu’aux années 1950, la conception de produits industriels est essentiellement perçue au travers de la « mécanique ») que d’un point de vue structurel (si diverses soient les technologies, la conception d’un produit industriel restera toujours tributaire de considérations liées à la résistance mécanique).

Cette polycopie est un outil destiné aux professionnels (en activité ou en formation). Il permettra à chacun de mener à bien les projets de construction mécanique ; car pour choisir et assembler les différents composants, le technicien ou futur technicien sera aidé par l’analyse des fonctions remplies par ces composants, les bases des calculs à entreprendre, les conditions d’emplois, voire pour certains les indications de prix contient. Il se situe dans le cadre d’une pédagogie active par laquelle l’apprenant devient de plus en plus autonome, recherchant lui-même les informations et les connaissances dont il a besoin pour résoudre les problèmes qui se posent et mener à bien les réalisations qui lui sont demandées.
Le polycopié est structuré en neuf chapitres.
Dans le premier chapitre, nous présenterons tout d’abord des généralités sur le domaine de la construction mécanique, quelques notions de base de calcul RDM.
Le second chapitre présent les assemblages mécanique dans la construction. Le troisième chapitre est consacré à l’emmanchement et frettage. Le quatrième chapitre présent les roulements, principe de calcule de la durée de vie des roulements, types de montage ansai que la méthode de désignation. Dans le cinquième chapitre on a traite les problème de transmission et transformation du mouvement, les déférents méthodes, et les rapports de transmission. Le sixième chapitre est consacré pour traité en détail les engrenages, c’est un complément de la chapitre précédent.

Cette étude porte à la simulation numérique d'écoulement diphasique vertical ascendant dans une conduite annulaire en utilisant le code de calcul commercial Fluent. La conduite est de diamètre interne DT=12.7 mm et externe DC=38.1 mm et de longueur L=16 m, est la même que celle utilisée par Das et al. Cette étude est effectuée pour une vitesse du gaz variable et à une vitesse de liquide constante égale à 0.14m/s. Les régimes à bulles, à poche (ou à bouchons de liquide), à forte coalescence et annulaire sont observés et tracés par les champs des fractions volumiques de l'air. Les résultats obtenus sont validés et conformes avec ceux trouvés par de Das et al(1999).

Dans l'optique de la production d'électricité, l'énergie solaire est une source d'énergie propre et inépuisable. Actuellement les technologies de concentration solaire sont celles qui présentent le plus de possibilités pour une exploitation commerciale. Cette énergie peut être transformée en chaleur à haute température, par concentration de rayonnement solaire. Cette opération est réalisée à l’aide de capteurs appelés concentrateurs solaires. Les systèmes solaires à concentration offrent la possibilité de produire de l’électricité à partir de l’énergie solaire, Parmi ce type de concentrateurs, il y a les concentrateurs solaires paraboliques. Ces systèmes comportent en général une surface réfléchissante sous forme parabolique destinée à concentrer l’énergie solaire sur une surface absorbante. Dans ce travail de recherche une étude du capteur parabolique solaire a été réalisée sur la géométrie et la distribution des flux dans la région focale. Le diamètre de la parabole est un paramètre important pour déterminer la quantité du rayonnement de flux au point focal. La géométrie a été simulée à l'aide d’un logiciel open source (Tonatiuh) qui permet de modéliser une antenne parabolique et de simuler son comportement optique. La distribution du flux a ensuite été tabulée sur le graphique coordonné pour obtenir le diamètre.

In this work, we present a numerical study of mixed convection heat exchange in a cubic cavity of a laminar three-dimensional (3D) incompressible flow. This study predicted the behavior of the flow structure between Multi clear structure dominated by natural convection when the Reynolds number is small, and a Multi clear structure dominated by forced convection when the Reynolds number is high. First, we fix the Grashof number for the variable Reynolds number. Second, we vary the number of Grashof for which the Reynolds number is kept fixed. The results obtained give a clear comparison with those found in the literature it examines and explains the thermal and dynamic characteristics of the flow.

Quand une onde de choc oblique vient frapper une paroi plane, deux types de réflexions sont possibles. Suivant l'inclinaison relative des chocs par rapport à la direction de l'écoulement amont, on obtient, soit une réflexion régulière (RR), soit une réflexion de Mach (MR). A des nombres de Mach supérieurs à 2, 2, il existe une gamme d'angles d'incidence pour lesquels ces deux types de réflexions sont conjointement possibles. C'est le domaine de solutions duales, qui a conduit à l'hypothèse de l'existence d'un effet d'hystérésis dans la transition RR-MR. Le but d’est de retrouver numériquement le phénomène d’hystérésis observé lors des études expérimentales dans l’interférence des ondes de choc, plus particulièrement les interactions régulières et de Mach. Il est alors question de traiter ce problème par une étude numérique conçu sur le principe de schéma de capture de choc