Louvet, Pierre; Durivault, Jean.
CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Div. de Chimie1976
CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Div. de Chimie1976
AbstractAbstract
[en] The motion of a compressible viscous gas in a rapidly rotating cylinder closed at both ends is investigated by the linear theory. The rigid rotation state is perturbed slightly by source or sinks and by thermal gadients. The method of matched asymptotic expansions is used to find uniform solutions in powers of the Ekman number. In the Stewartson 1/3 layer along the side wall, the Ekman number epsilon at power 1/3 is taken of the same order of magnitude as the inverse of the square Mach number M; this allows to take correctly into account the radial compressibility effect, contrary to previous works. This method is also applied to detached layers and to Stewartson 1/4 layers where the product of epsilon at power 1/4 by the square Mach number M is zero. The pattern of the flow in these layers is strongly altered as compared to incompressible case
Original Title
gas centrifuges used for the enrichment of gaseous UF6
Primary Subject
Source
1976; 22 p; Symposium on singular perturbation problem and boundary layer theory; Lyon, France; 8 - 10 Dec 1976
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Durivault, Jean; Louvet, Pierre.
CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Genie Isotopique1976
CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Genie Isotopique1976
AbstractAbstract
[en] This paper deals with the flow calculation in a thermal countercurrent centrifuge at total reflux. Matched asymptotic expansions are used to find approximate solutions of Navier-Stokes equations which are assumed to be valid in the whole domaine. Convection and viscous dissipation disappear because of linearization, but compressibility is taken into account. Let epsilon be the Ekman number. The equations are solved in the inviscid core, in the horizontal Ekman layers of thickness 0 (epsilonsup(1/2) and in the Stewartson layer of thickness 0 (epsilonsup(1/3)), parallel to the axis. As the thermal convection is neglected, the Stewartson layer of thickness 0 (epsilon sup(1/4)) does not occur. The results show the importance of the recirculating mass-flow rate of order 0 (epsilonsup(1/3)) in front of the countercurrent mass-flow rate of order 0 (epsilonsup(1/2)). The temperature profile rules the pattern and the intensity of the recirculating flow
[fr]
Dans cette etude, on calcule l'ecoulement dans une centrifugeuse a contre-courant thermique pur et a rejet nul. La methode appliquee est celle des developpements asymptotiques raccordes, les equations de Navier-Stokes etant supposees valables dans l'ensemble de l'ecoulement. Si la convection et la dissipation visqueuse disparaissent dans la linearisation des equations, par contre les effets de compressibilite sont pris en compte. Designant pas epsilon le nombre d'Ekman, nous avons calcule les grandeurs caracteristiques de l'ecoulement dans le coeur, dans la couche d'Ekman d'epaisseur epsilonsup(1/2) sur les plateaux de la centrifugeuse et dans la couche de Stewartson d'epaisseur epsilonsup(1/3) le long des parois. En l'absence de convection la couche parietale d'epaisseur epsilonsup(1/4) disparait. Les resultats obtenus montrent l'importance du flux de recirculation d'ordre epsilonsup(1/3) par rapport au flux de contre-courant d'ordre epsilonsup(1/2) cree par les couches d'Ekman dans la couche parietale. Le profil axial de temperature agit quantitativement et qualitativement sur la recirculation parietaleOriginal Title
Etude theorique de l'ecoulement dans une centrifugeuse a contre courant thermique
Primary Subject
Source
Mar 1976; 40 p
Record Type
Report
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Durivault, Jean; Louvet, Pierre; Rouvillois, Gildas; Soubbaramayer.
CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Genie Isotopique1976
CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Genie Isotopique1976
AbstractAbstract
[en] The motion of a compressible gas in an isotopic centrifuge closed at both ends (case of total recirculation) is investigated by the linear theory. The equilibrium state is a rigid rotation and the perturbed flow is obtained by heating slightly one end plate of the cylinder and cooling the other one
Primary Subject
Source
1976; 4 p; Euromech colloquium: separation phenomena in gas mixture flows; Karlsruhe, Germany, F.R; 6 - 9 Sep 1976; Copies available from Service de Documentation, CEN Saclay, BP No 2, 91190 Gif-sur-Yvette (France)
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] The gas compressibility alters the pattern of the side-wall Stewartson 1/3 layer in a rapidly rotating cylinder. Let epsilon be the Ekman number, as epsilon (at the power 1/3) is of the order of magnitude of the square Mach number, the method allows the recirculating mass flow rate to be closed, neglecting terms of the order epsilon (at the power 1/3)
[fr]
On etudie en fluide compressible, la structure de la couche de Stewartson un tiers le long de la paroi laterale d'un cyclindre en rotation rapide. Le nombre d'Ekman (epsilon) a la puissance un tiers etant du meme ordre de grandeur que l'inverse du nombre de Mach au carre, on assure la fermeture du debit de recirculation a un terme d'ordre epsilon (a la puissance 1/3) presOriginal Title
Etude de la couche de Stewartson compressible dans une centrifugeuse a contre-courant thermique
Primary Subject
Record Type
Journal Article
Journal
C. R. Hebd. Acad. Sci., Ser. B; v. 283(4); p. 79-82
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Flow and isotope separation factor are investigated in a thermal countercurrent gas centrifuge with conducting side wall. If the latter is maintained isothermal, the closed circulation in the Stewartson layer is suppressed and the separation efficiency strongly improved
[fr]
L'ecoulement et le facteur de separation isotopique sont calcules dans une centrifugeuse a contre-courant thermique avec paroi conductrice. Si celle-ci est maintenue isotherme, la recirculation dans la couche de Stewartson est supprimee et le rendement de sepration nettement amelioreOriginal Title
Contrecourant thermique et separation isotopique dans une centrifugeuse a paroi laterale isotherme
Primary Subject
Record Type
Journal Article
Journal
Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences. Serie B; v. 283(2); p. 17-19
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue