Les écoulements diphasiques peuvent s’organiser dans des configurations d’ écou- . pour l’amortissement diphasique dans les écoulements `a bulles et. Dans ce mémoire, on s’intéresse à la simulation des écoulements liquide-vapeur en transition de phase. Pour décrire ces écoulements, une approche bifluide. lumes Finis des écoulements diphasiques eau-vapeur. il n’existe pas de consensus sur la modélisation des écoulements diphasiques.

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Dans le processus de developpement d’avion, ecoulemenrs solution retenue doit satisfaire de nombreux criteres dans de nombreux domaines, comme par exemple le domaine de la structure, de l’aerodynamique, de la stabilite et controle, de la performance ou encore de la securite, tout en respectant des echeanciers precis et minimisant les couts.

Modeling of the re-starting of waxy crude oil flows in pipelines; Modelisation du redemarrage des ecoulements de bruts paraffiniques dans les conduites petrolieres. A maximum in the heat exchange and pressure-drop coefficients was observed when the pitch equals about eight times the height of the thread.

Les migrants de Beyrouth.

At the microscopic scale, the reconstitution of crack opening – fluid percolation – crack sealing stages is delicate. Finally, the implementation of a turbulence model and the introduction of a reconstruction process for the interfacial area are investigated in order to refine the description of the interfacial transfers.

Then, it is clear that, in addition of the standard parameters which are to be taken into account, it is necessary to consider the type of flow the suspension is submitted to. In fact, following the pioneering work of Esaki and Tsu inthe study of these two-dimensional semiconductor heterostructures has developed rapidly, both from the point of view of basic physics and of applications.

Gas transport through porous media; Sur le transport des gaz a travers les milieux poreux. In this thesis, we are interested in using domain decomposition methods for solving fluid flows in faulted porous media. Une nouvelle geometrie de reacteur est proposee pour intensifier les transferts de matieres autour des grains de catalyseur et accelerer les vitesses superficielles des fluides: The name Les Impatients reinforces the idea that the organization does not consider those attending its workshops as patients, but rather creators who are eager to heal, develop their craft and find their place in society.

Il comporte certaines recommandations en vue de recherches futures indispensables et donne des conseils sur la facon de minimiser les effets de deversements de petrole dans le milieu marin canadien. Experimental study of heat exchange coefficients, critical heat flux and charge losses, using water-steam mixtures in turbulent flow in a vertical tube; Etude experimentale des coefficients d’echanges thermiques, des flux de chaleur critiques et des pertes de charge avec des melanges eau-vapeur en ecoulement turbulent dans un tube vertical.


These models are hyperbolic under some physical assumptions and can be written under a nonconservative vectorial system. As a result a detailed study has been made of the work of C. Do not hesitate to show your support at their farewell party to be held on Monday 7 October, from 4 to 6 pm in front of the St Genis-Pouilly Mairie city Hall.

When it comes to validating physical models of these flows, the analytical process highlights the main descriptive parameters of local flow conditions: First, a theoretical thermodynamic framework is constructed to describe the liquid-vapor mixing.

As the phenomena are extremely rapid and they take place in very small geometries, experimental investigations are pretty hard to manage. Une detection optique simultanee de la presence des phases permet un traitement conditionnel de la base de donnees. Des rugosites du type ‘interrupteur de couche limite’ etaient realisees au moyen de filets triangulaires, de 0,2 a 0,4 mm de hauteur usines dans l’epaisseur du tube ou de fils de laiton, ou de verre, enroules sur un tube lisse.

The temporal behaviour of two wall models algebraic and zonal wall models were studied and showed that a zonal model produced better results when used in the simulation of unsteady flows.

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fcoulements The results obtained are in good agreement with those diphasiqques both from the graphical method using the characteristics ecolements from experimental recorded data.

This work deals with the discretization of Navier-Stokes equations using different finite element methods adapted to the problem of two-phase flows. It is shown that those dealing with exchange coefficients can only be applied in a first approximation in cases where exchange by convection is preponderant, and only below the critical flux. Their we make a revue of the two-phase models, defining their validity domains.

Using suitable numerical methods, we have performed a systematic study of these parameters as a function of the topology of the fracture network and matrix to fracture permeability contrast. Ecoulements intermittents de gaz et de liquide en conduite verticale Intermittent Gas and Liquid Flows in a Vertical Pipe. The originality lies in the approximation of the immersed boundary by an approximate interface derived from the fictitious domain Cartesian mesh, which is generally not boundary-fitted to the physical domain.

The work presented here investigates the capabilities of numerical research tools for the prediction of combustion instabilities. Experiments were made both in free convection and forced convection, the latter case with and without an ciphasiques source of ionisation. These parts can ecoulemeents identified as large-scale hydrodynamic layers and separately coarsened in the large-scale simulation model. Le developpement de methodes ameliorant la precision des methodes existantes tout en gardant un cout de calcul faible permet d’obtenir un niveau de fidelite plus eleve dans les premieres phases de developpement du projet et ainsi grandement diminuer les risques associes.


C’est pourquoi les auteurs ont adopte une technique qui consiste a Introduire dans l’eau de la chaudiere une quantite calculee de sodium On a etabli un modele de variation continue du taux de vide dans ecoulemenys canal.

les ecoulements diphasiques: Topics by

To fix the ideas we consider the piston problem and we show that in some cases more conditions must be added to the conservation laws in order to provide sufficient data for the unique determination of the propagation process. Les deux methodes donnent des resultats concordants en particulier pour les ecoulements a bulles. The organization’s originality resides in the exploration of the links between the work of the participants and that of professional artists.

Both the engineer and the physicist’s points of view are taken into consideration: It seems that the dimensions of the riser have a determining effect: The heat transfer parameters were determined experimentally in electrically heated tube bundles for turbulent flow parallel ecoulsments the axis. The use of Chapman-Enskog expansions enables us to link the different existing models to each other.

The turbulent flows encountered in nuclear reactor thermal hydraulic studies or fossil-fired diohasiques thermo-aerodynamic analyses feature widely varying characteristics, frequently entailing heat transfers and two-phase flows so that modelling these phenomena tends more and more to involve coupling between several branches of engineering.

The document is a PhD thesis divided in 6 chapters and two annexes. Both reactive and non-reactive regimes are successfully compared with experimental data in terms of mean temperature and mean and RMS velocities. Quatre types de detonation et quatre types de deflagration sont etudies. A new one-velocity one-pressure dissipative model is then proposed, where the arising of second-order terms enables ecoulemfnts to take into account unbalances between the phase velocities.

Diop de Dakar, pp.

An experimental installation has ecouoements carried out. The pressure and temperature range within which the oil and gas-condensate properties must be known coupled with the fact that the overall composition of.

Pratiquement aucun travail fondamental n’a encore ete publie sur ce. Cette particularite permet de definir une concentration volumique locale et d’etablir des equations aux applications multiples.