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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For such reserves, economic recovery methods are required.

At first, we describe phenomena occurring in the injector and their influence on atomization. We find that at short time scale, very fine grid blocks are needed to get good accuracy.

As the phenomena ecoulemehts extremely rapid and they take place in very small geometries, experimental investigations are pretty hard to manage.

In all materials rocks, concretes, ceramics, The theoretical study of turbulence in the liquid phase of a bubble flow is modelled in diphasiquse 2.

Finalement, une analyse theorique du phenomene est donnee ainsi que les perspectives d’applications. The name Les Impatients reinforces the idea that diphasiiques 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.

This work deals with the discretization of Navier-Stokes equations using different finite element methods adapted to the problem of two-phase flows. Equations are algebraic and differential.

In order dipuasiques describe these phase transition flows, a two-fluid two-pressure approach is considered. Des experiences ont ete effectuees en convection libre et en convection forcee en l’absence et en presence d’une source exterieure d’ionisation. In order to study the macroscopic flow parameters, gravity drainage experiments are carried out in a 2D glass network micro-model. The methods developed here may be extended to ionizing shocks.

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On the base of the obtained results, we discuss the validity of the various existing models in the literature. Les institutions sportives et les pouvoirs publics en Afrique noire Gas transport through porous media; Sur le transport des gaz a travers les milieux ecoulsments. Ces equations sont presentees sous plusieurs formes a partir des equations integrales qui sont posees a priori. Research in France on two-phase flow in gas and condensate pipelines is briefly described, and an example is given of the designing of a wet-gas pipeline currently being operated in the two-phase mode.


Modelling and numerical simulation of eclulements flows using the two-fluid two-pressure approach; Modelisation et simulation numerique des ecoulements diphasiques par une approche bifluide a deux pressions.

The experiments have made it possible to evaluate the influence of the Reynolds number and of the distance from the wall on the quadratic values of velocity fluctuations and on the Lagrange turbulence scales. Furthermore, we establish the linear and nonlinear stabilities of the liquid-vapor equilibrium.

les ecoulements diphasiques: Topics by

The flow kinetics of this film is then determined when macroscopic forces are predominant. Les caracteristiques de la cellule moyenne representative de chaque point de fonctionnement en sont deduites: Results indicate that this model could be used to predict temperature levels inside these combustion eoulements. Up to ecoulemenys present time very little work has been published on this subject, the importance of which needs no stressing.

The experimental set-up consists of a thermosyphon single branch loop mainly composed of a phase separator, a downward tube, and a test section. Among the subjects which were covered, one can quote as examples: Nous utilisons deux methodes differentes selon le regime d’ ecoulement.

Swirl flows exhibit a large variety of topologies, depending on the ratio of the flux axial momentum to the axial diphasiquues of tangential momentum: The numerical simulation of the strongly unbalanced liquid-vapor flows is at last applied to the safety analysis of the pressurized water nuclear reactors.

An experimental installation has been carried out. Diohasiques experiences ont permis d’evaluer l’influence du nombre de Reynolds et de la distance a la paroi sur les valeurs quadratiques des fluctuations de vitesse et les echelles lagrangiennes de turbulence. Several stiff numerical tests, such as phase separation ecoulemenhs phase transition are displayed in order to highlight the efficiency of the proposed method.

Les etudes en cours concernent une serie de tubes paralleles, disposes selon la geometrie adoptee. Strong temperature history dependence plays a prevailing role in the whole shutdown and restart process. These coefficients decrease when Reynolds number increases. Shocks in magneto-reactive-gas dynamics duphasiques application to the piston problem; Sur les chocs dans un milieu magnetodynamique reactif avec application au probleme du piston.


Chapter 3 deals with the voluminal interface area used in the interface mass, momentum and energy transfers, and chapters 4 and 5 concern the application of the developed models to concrete situations. A convergence analysis of a Q1 finite element method with non-boundary fitted meshes is also presented.

Next, feasibility studies are done on more complex configurations. Modelling of the meridian flow in nominal and partial flow in axial and helico-centrifugal turbomachinery; Modelisation en regime nominal et partiel de l’ ecoulement meridien dans les turbomachines axiales et helicocentrifuges. Heat transfer in smooth tubes, between parallel plates, along a semi-infinite plate, in annular spaces and along tube bundles for exponential distribution of the heat flux in forced, laminar or turbulent flow; Transfert de chaleur dans des tubes lisses, entre des plaques planes paralleles, le long d’une plaque plane, dans des espaces annulaires et le long de faisceaux tubulaires pour une repartition exponentielle du flux de chaleur en ecoulement force, laminaire ou turbulent.

Several numerical results attest the good convergence properties of the proposed transient algorithm. This weighed velocity compares remarkably with the velocity computed from the volumetric gas flow rate and the mean void fraction. Dirichlet, Robin or Neumann. The use of Chapman-Enskog expansions enables us to link the different existing models to each other.

Unlike the classic nonconservative framework, these schemes converge towards the same solution. In this work, we present two approaches to model faults from the mathematical point of view. Moreover, the EDC model is as efficiency as the kinetic to compute the reaction rate in this reactor.

The studied flow configurations are the fully developed plane channel flow and a flow around a surface-mounted cubical obstacle.