Search results for "FD"
showing 10 items of 483 documents
WCLL breeding blanket design and integration for DEMO 2015: status and perspectives
2017
Abstract Water-cooled lithium-lead breeding blanket is considered a candidate option for European DEMO nuclear fusion reactor. ENEA and the linked third parties have proposed and are developing a multi-module blanket segment concept based on DEMO 2015 specifications. The layout of the module is based on horizontal (i.e. radial-toroidal) water-cooling tubes in the breeding zone, and on lithium lead flowing in radial-poloidal direction. This design choice is driven by the rationale to have a modular design, where a basic geometry is repeated along the poloidal direction. The modules are connected with a back supporting structure, designed to withstand thermal and mechanical loads due to norma…
Computational thermofluid-dynamic analysis of DEMO divertor cassette body cooling circuit
2018
Abstract Within the framework of the Work Package Divertor, Subproject: Cassette Design and Integration (WPDIV-Cassette) of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. The research activity has been carried out following a theoretical-computational approach based on the finite volume method and adopting a qualified Computational Fluid-Dynamic (CFD) code. Fully-coupled fluid-structure CFD analyses have been carried out for the recently-revised cassette body cooling circuit under nominal steady state conditions, imposing a non-uniform sp…
Tenuta e rinnovamento della nobiltà feudale nella Sicilia spagnola (XVI-XVII secc.)
2022
Il saggio analizza sulla base di un ampio ricorso a fonti primarie i fattori di consolidamento e di rinnovamento della nobiltà feudale nella Sicilia spagnola (secc. XVI-XVII) The essay analyzes the factors of consolidation and renewal of the feudal nobility in Spanish Sicily (16th-17th centuries) on the basis of extensive recourse to primary sources.
Family involvement in the intensive care unit in four Nordic countries
2021
BackgroundRelevance to clinical practice The findings from the study highlighting family involvement, high-quality communication and flexible visiting policy as central aspects of family care may inspire clinicians to identify aspects of everyday family care in their ICUs calling for further improvement.Aims and objectivesTo describe family involvement, communication practices and visiting policies in adult ICUs.DesignA cross-sectional survey.MethodA questionnaire consisting of 11 sections was developed, pilot tested and e-mailed to 196 ICUs. The participants were intensive care nurses in adult ICUs in four Nordic countries.ResultsThe survey was conducted in October to December 2019. The re…
Analytical and Numerical Assessment of Thermally Induced Pressure Waves in the IFMIF-DONES Liquid-Lithium Target
2020
The intended steady-state operation conditions of the International Fusion Materials Irradiation Facility-DEMO Oriented Neutron Source (IFMIF-DONES) target system are based on the D+ beam stationary running at full nominal power (5 MW). Nevertheless, critical situations can occur in the case of unavoidable sudden events like beam trips. The instantaneous variation in the heating power deposited in lithium when the beam is rapidly switched between ON-and OFF-states leads to thermal expansion, which is compensated by the compression of the target material, resulting in locally high pressures and a pressure wave propagating through the target toward the back wall. Besides the tensile stress of…
Hydraulic analysis of EU-DEMO divertor plasma facing components cooling circuit under nominal operating scenarios
2019
Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by University of Palermo and ENEA to investigate the steady state thermal-hydraulic behaviour of the DEMO divertor cassette cooling circuit, focussing the attention on its Plasma Facing Components (PFCs). The research campaign has been carried out following a theoretical-computational approach based on the Finite Volume Method and adopting the commercial Computational Fluid-Dynamic code ANSYS-CFX. A realistic model of the PFCs cooling circuit has been analysed, specifically embedding each Plasma Facing Unit (PFU) cooling chann…
On the numerical assessment of the thermal-hydraulic operating map of the DEMO Divertor Plasma Facing Components cooling circuit
2020
Abstract Within the framework of the Work Package DIV 1 - “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by University of Palermo and ENEA to investigate the thermal-hydraulic behaviour of the DEMO divertor cassette cooling system, focussing the attention on the 2018 configuration of the Plasma Facing Components (PFCs) circuit consistent with the DEMO baseline 2017. The research campaign has been carried out following a theoretical-computational approach based on the finite volume method and adopting the commercial Computational Fluid-Dynamic (CFD) code ANSYS CFX. A steady-state CFD analysis has been carried out for the …
On the thermal-hydraulic optimization of DEMO divertor plasma facing components cooling circuit
2018
Abstract Within the framework of the Work Package Divertor, Subproject: Cassette Design and Integration (WPDIV-Cassette) of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. Attention has been focussed on the divertor Plasma Facing Components (PFCs) cooling circuit and a parametric analysis has been carried out in order to assess the potential impact of proper layout changes on its thermal-hydraulic performances, mainly in terms of coolant total pressure drop, flow velocity distribution and margin against critical heat flux occurrence. The r…
Hydraulic assessment of an upgraded pipework arrangement for the DEMO divertor plasma facing components cooling circuit
2021
Abstract In the context of the Work Package DIVertor (WPDIV) of the EUROfusion action, a research campaign has been carried out by University of Palermo in cooperation with ENEA to assess the thermal-hydraulic performances of the DEMO divertor cooling system, concentrating the attention on its 2019 Plasma Facing Components (PFCs) configuration, relevant to DEMO baseline 2017. The research activity has been performed following a theoretical-numerical technique based on the finite volume method and adopting the well-known ANSYS CFX CFD code. The PFCs cooling circuit thermal-hydraulic performances under nominal steady-state conditions, assessed mainly in terms of coolant total pressure drop, c…
Implementation Aspects of 3D Lattice-BGK: Boundaries, Accuracy, and a New Fast Relaxation Method
1999
In many realistic fluid-dynamical simulations the specification of the boundary conditions, the error sources, and the number of time steps to reach a steady state are important practical considerations. In this paper we study these issues in the case of the lattice-BGK model. The objective is to present a comprehensive overview of some pitfalls and shortcomings of the lattice-BGK method and to introduce some new ideas useful in practical simulations. We begin with an evaluation of the widely used bounce-back boundary condition in staircase geometries by simulating flow in an inclined tube. It is shown that the bounce-back scheme is first-order accurate in space when the location of the non…