Search results for "Enclos"

New solutions for prefabricated secondary substations in the view of sustainability

2016

The secondary substations will assume an important role as “smart nodes” of the smart grid. So in few years there will be a widespread dissemination on the territory of this apparatus. Consequently, great care have to be taken not only on safety issues, but also on the constructive methodology, in order to determine low environmental impact and decommissioning cost. This paper focuses on innovative solutions for the realization of prefabricated secondary substations, in the direction of sustainability. Innovative layout and enclosure topologies have been here taken into account. In particular, by considering that the substation concrete box is, at the same time, uneconomical and with strong…

Low-Prandtl Number Natural Convection in Volumetrically Heated Rectangular Enclosures - III. Shallow Cavity, AR=0.25

2001

Abstract Natural convection in a volumetrically heated rectangular enclosure filled with a low-Prandtl number (Pr=0.0321) fluid was studied by direct numerical two-dimensional simulation. The enclosure had isothermal side walls and adiabatic top/bottom walls. The aspect ratio was 4 and the Grashof number Gr, based on conductive maximum temperature and cavity width, ranged from 3.79 × 104 to 1.26 × 109. According to the value of Gr, different flow regimes were obtained: steady-state, periodic, and chaotic. The first instability of the steady-state solution occurred at Gr≈3×105; the resulting time-periodic flow field consisted of a central rising plume and of convection rolls, periodically ge…

MHD free convection in a liquid-metal filled cubic enclosure. II. Internal heating

2002

The buoyancy-driven magnetohydrodynamic flow in a liquid-metal filled cubic enclosure was investigated by three-dimensional numerical simulation. The enclosure was differentially heated at two opposite vertical walls, all other walls being adiabatic, and a uniform magnetic field was applied orthogonal to the temperature gradient and to the gravity vector. The Rayleigh number was 105 and the Prandtl number was 0.0321 (characteristic of Pb–17Li at 573 K). The Hartmann number was made to vary between 102 and 103 and the electrical conductance of the walls between 0 and ∞. The continuity, momentum and enthalpy transport equations, in conjunction with a Poisson equation for the electric potentia…

MHD free convection in a liquid-metal filled cubic enclosure. I. Differential heating

2002

Natural convection heat transfer in a partially—or completely—partitioned vertical rectangular enclosure

1991

Abstract The effect of symmetric partitions protruding centrally from the end walls of a rectangular vertical enclosure on heat transfer rates is investigated numerically. The enclosure has opposite isothermal walls at different temperatures. The Rayleigh number is varied from 10 4 to 10 7 and the aspect ratio from 0.5 to 10. The thickness of the partitions is fixed and equal to one tenth of the width of the enclosure. Their non-dimensional length ( L / H ) is varied from 0 (non-partitioned enclosure) to 0.5 (two separate enclosures). The effect of different thermal boundary conditions at the end walls and at the partitions is included in the investigation.

On natural convection in a single and two zone rectangular enclosure

1992

Abstract Convective heat transfer was investigated numerically for rectangular enclosures both undivided and divided in two zones by a vertical partition, and having opposite isothermal walls at different temperatures. The aspect ratio was varied from 0.1 to 16 and the Rayleigh number from 3.5 ∗ 10 3 to ∗ 10 7 (non-partitioned enclosures) and from 1.0 ∗ 10 5 to 1.6 ∗ 10 8 (partitioned enclosures). The thickness and conductivity of the partition were varied. The end wall thermal boundary conditions were adiabatic or LTP (Linear Temperature Profile). The continuity, momentum and energy equations for a 2-D laminar steady flow were solved under the Boussinesq approximation by using a finite-dif…

One-dimensional Mixed MHD Convection

2006

The parallel, fully developed flow of an electrically conducting fluid between plane parallel walls under the simultaneous influence of a driving pressure head, buoyancy, and magnetohydrodynamic (MHD) forces is studied. The fluid is assumed to be internally heated and the flow is modeled as one-dimensional and incompressible, while the Boussinesq approximation is adopted for the buoyancy terms. Analytical solutions are obtained for temperature, velocity and electrical potential under different electrical boundary conditions, forced to natural convection intensity ratios and values of the magnetic induction. Generalized working charts are presented which synthetically describe the system''s …

Bonneuil-en-France (95), Aéroport du Bourget, zone nord-ouest. Un village du haut Moyen Âge, une petite exploitation agricole gallo-romaine, une nécr…

2022

Les fouilles ont eu lieu en 2016-2017 sur une surface de près de 9 hectares. Elles faisaient suite au diagnostic de 2007 (RO : T. Capararro, Inrap) et à une première fouille réalisée en 2010 sur une surface de 1,5 hectares (RO : G. Bruley-Chabot, Inrap). Hormis quelques éléments épars du Paléolithique Moyen au Néolithique, les premières traces d'occupation remontent à l'âge du Bronze final (quelques fosses et un enclos circulaire de plus de 330 m2 ). Le Hallstatt et La Tène A sont représentés par un faible nombre de structure. Une importante nécropole date de La Tène B2-C1. Elle regroupe 42 inhumations et une probable crémation. Si les ossements sont pour la plupart très mal conservés, le m…

Policing and Site Protection, Guard Posts, and Enclosure Walls

2015

Les établissements palissadés en Champagne - Etat de la question

2022

La multiplication des découvertes d'enclos palissadés en Champagne depuis le début des années 2000 avait permis en 2010 une première synthèse régionale et de replacer ce phénomène dans un espace plus vaste de l'Atlantique à la Bavière (Desbrosse, Riquier, 2012). Le corpus s'est depuis enrichi et la variété des données exhumées montre que nous sommes encore dans une phase exploratoire. En conséquence, il convient de tenter de répondre à un nombre réduit de questions cruciales, relatives à l'évolution du corpus, aux techniques de construction et au plan d'ensemble, à la chronologie de ces établissements, ainsi qu'à leur géographie à différentes échelles, avant d'aborder la question centrale d…