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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During the shutdown, since the temperature decreases in the pipeline, the gel-like structure builds up and the main difficulty concerns the issue of restarting. The effect of surface roughness on the heat fiphasiques and pressure-drop coefficients; Influence des rugosites de paroi sur les coefficients d’echange thermique et de perte de charge. Bolletino del Laboratorio di Resulting from century-long conflicts between producers and merchants, vineyards have developped out of “distinction” phenomenons which in the Bordeaux region gave birth to “crus” vintages.

Usually, the development of such alterations leads to a massive sealing of the fractures vein alterations and of the fissures fluid inclusion planes and microcracks, pervasive alteration. Est-il dans le monde ou le contient-il?

les ecoulements diphasiques: Topics by

ecoilements Such identified terroirs had to be defended: La Tentation et les savoirs. Conservation phase equations integrated along the cross-section were processed by different time-averaged operators so as to develop a cellular model including a limited number of constitutive equations required for its closure.

Swirl flows exhibit a large variety of topologies, depending on the ratio of the flux axial momentum to the axial flux of tangential momentum: The modelling allows to take into account more accurately the geometry of the interface and ensures a better quantification of leachate flow rates than using existing methods.

Provided with these schemes, the whole numerical method preserves the liquid-vapor equilibria.

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.


Improvements of manufacturing process has opened up the possibility of industrial scale manufacturing of up to one million, nm in diameter, filaments.

Cette etude a pour but de permettre une description fine de l’ ecoulement. Finally, we applied our technique to well-test interpretation in fractured media by comparing large scale solutions to high resolution direct simulations.

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Several solutions are proposed which seem to fulfill these expectations. The methods developed here may be extended to ionizing shocks. These closure laws comply with an entropy inequality.

Two-phase cooling fluids advantages over single-phase fluids are presented with their thermophysical characteristics: Using resistive probes and photographic techniques, we have determined the flow patterns and developed diagrams to indicate the boundaries between the various patterns: The author first proposes an overview of slug flow regimes: Le taux de dissociation est surtout fonction de la temperature de paroi et du debit en masse total d’ammoniac; il depend peu de la temperature d’entree du gaz et est pratiquement independant de la pression.

The description of such fields is based on a probabilistic approach leading to an estimate of the characteristics of the reservoir rock, i. The research which makes up this thesis is concerned both with the problems of adsorption an chromatographic columns and of catalysis, which involve the surface properties of these solids, and with problems of isotope separation by gaseous diffusion.

Have you forgotten your login? The organization called ” Les Impatients” was founded in Special attention is paid to problems raised by the transposition of laboratory results obtained on small samples to a field. A thorough analytical study is carried out for laminar flows. Comportements Sexuels parmi les Adolescents et Jeunes. Both approaches provide encouraging results and allow a surface-mounted cubical obstacle.

Ce que disent les cartes, etc. Calculation programme for transient thermo-pneumatic flows; Programme de calcul pour les ecoulements transitoires thermopneumatiques. These test cases are re-run for each new version, so that the sets of test cases systematically benefit from the gradually upgraded functionalities of the codes.

Modelling and numerical simulation of two-phase flows using the two-fluid two-pressure approach; Modelisation et simulation numerique des ecoulements diphasiques par une approche bifluide a deux pressions. The presence of this uncorrelated motion leads to stress terms in the Eulerian balance equation for the particle momentum.


Different numerical schemes have been tested to improve the computation accuracy. This internal structure is investigated for the eight types of process under the influence of the combustion mechanism and the dissipative ecoluements viscosities, electrical and thermal conductivity.

A maximum in the heat exchange and pressure-drop coefficients was observed when the pitch equals about eight times the height of the thread.

Furthermore, a new relaxation scheme is proposed to approach the interfacial transfers. When based on suitable kinetic unwind schemes, the algorithm can compute flow regimes evolving from mixture to single phase flows and vice versa. The target of this research is to obtain, from experimental observations, the microscopic rules of flow by films taking into account the elementary mechanisms controlling the displacement of fluids.

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.

Results show that reduced upstream pressure is the main parameter, thus indicating that a model can be validated using minimal fluids. For stable flow in stratified media, we show that the front is stationary by parts in the reservoir.

The very complicated evolution of the radial structure is shown by the measurement of the mean bubble flux at several points in the tube.

Les etudes en cours concernent une serie de tubes paralleles, disposes selon la geometrie adoptee. Such numerical methods have the drawback of being numerically very expensive for practical applications. This work studies heat and mass transfer characteristics of two phase He I in a natural circulation loop. The use of Chapman-Enskog expansions enables us to link diphasoques different existing models to each other.

High Reynolds numbers are un-affordable by direct simulation DNSand simulations must either be performed by solving averaged equations RANS diphasiqkes, or by solving only the large eddies LESboth using a wall model.

Two-phase flows during a discharge of liquefied gases, initially at saturation.

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