Analytical and Computational Analysis of Turbulent Bouyant Jets in the Containment Atmosphere

2008 ◽  
Author(s):  
Enrico Deri ◽  
Matteo Bucci ◽  
Etienne Studer ◽  
Daniele Abdo
Keyword(s):  
Large Scale ◽  
Computational Analysis ◽  
Severe Accident ◽  
Buoyant Jets ◽  
Computational Tools ◽  
Experimental Campaign ◽  
Hydraulic Conditions ◽  
Computer Codes ◽  
Computational Fluid Dynamics Cfd

In case of severe accident, complex thermal-hydraulics phenomena are expected to occur in the containment atmosphere. To investigate and understand these phenomena, fundamental for nuclear safety and design, major efforts are being spent all over the world. A new OECD project, named SETH-2, is conceived to generate relevant experimental data, useful to improve the modeling capabilities of the computer codes aimed to predict post-accident containment thermal-hydraulic conditions. The Commissariat a` l’Energie Atomique (CEA) contributes to the project performing experiments within the large scale MISTRA facility. Tests are proposed to investigate mixing phenomena promoted in a stratified containment. In particular, one of these test series concerns the interaction of buoyant jets with a stratified atmosphere. The present work is aimed to develop and validate computational tools useful to support the design of this experimental campaign and to analyze the actual MISTRA tests. In this aim, two different models have been implemented for turbulent buoyant jets in a stratified atmosphere: an engineering analytical model for a fast characterization of flow structures and a finite elements computational fluid dynamics (CFD) model that allows a detailed analysis of local phenomena. The models have been successfully validated for vertical buoyant jets in uniform atmosphere. Further experimental and numerical activities are illustrated, aimed to carry out the validation with stratified atmosphere and inclined injections.

scholarly journals Apron and Cutoff Wall Scour Protection for Piano Key Weirs

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2332
Author(s):  
Wyatt Lantz ◽  
Brian Mark Crookston ◽  
Michele Palermo
Keyword(s):  
Large Scale ◽  
Open Channel ◽  
Control Structure ◽  
Cutoff Wall ◽  
Specific Design ◽  
Experimental Campaign ◽  
Hydraulic Conditions ◽  
Weir Height ◽  
Scour Protection ◽  
Design Guidance

Piano key (PK) weirs are used in a variety of flow control structure applications, including spillway crests and open channel diversion structures. However, to the best of authors’ knowledge, structure-specific design guidance for scour mitigation is still needed. To fill this gap of knowledge, a systematic experimental campaign was conducted by testing different configurations of horizontal aprons with a cutoff wall. Protection structures were located at the toe of the PK weir. Namely, experiments were performed at large-scale to assess the effect of three apron lengths on downstream scour hole geometry under different hydraulic conditions. It was observed that a horizontal apron deflects the plunging jets originating from the PK weir, thus significantly reducing scour. Experimental evidence allowed corroboration that significant scour depth reduction occurs for an apron length 1.5 times the weir height, with longer aprons found to provide marginal benefits. Finally, also provided herein are tools to estimate the main scour characteristics and help practitioners in optimizing apron design.

Neutronic Analysis of the European Sodium Fast Reactor: Part I - Fresh Core Results

2020 ◽  
Author(s):  
Emil Fridman ◽  
Francisco Álvarez Velarde ◽  
Pablo Romojaro Otero ◽  
Haileyesus Tsige-Tamirat ◽  
Antonio Jiménez-Carrascosa ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Core State ◽  
Computational Tools ◽  
Horizon 2020 ◽  
The Core ◽  
Continuous Energy ◽  
Sodium Fast Reactor ◽  
Computer Codes ◽  
Calibration And Verification

Abstract In the framework of the Horizon 2020 project ESFR-SMART (2017-2021), the European Sodium Fast Reactor (ESFR) core was updated through a safety-related modification and optimization of the core design from the earlier FP7 CP-ESFR project (2009-2013). This study is dedicated to neutronic analyses of the improved ESFR core design. The conducted work is reported in two parts. Part I deals with the evaluation of the safety-related neutronic parameters of the fresh Beginning-of-Life (BOL) core carried out by 8 organizations using both continuous energy Monte Carlo and deterministic computer codes. In addition to the neutronics characterization of the core, a special emphasis was put on the calibration and verification of the computational tools involved in the analyses. Part II is devoted to once-through and realistic batch-wise burnup calculations aiming at the establishing of the equilibrium core state, which will later serve as a basis for detailed safety analyses.

Computational Analysis and Characterization of Cockpit Environmental Control System of a Fighter Aircraft in Humid Environment

2014 ◽  
Vol 629 ◽  
pp. 263-269 ◽  
Author(s):  
Muhammad Ayaz ◽  
J. Masud
Keyword(s):  
Control System ◽  
Computational Analysis ◽  
Environmental Control ◽  
Great Flexibility ◽  
Fighter Aircraft ◽  
Efficient Operation ◽  
Analysis Techniques ◽  
Humid Environment ◽  
Computational Fluid Dynamics Cfd

he Environmental Control System (ECS) is an important part of any fighter aircraft and has far reaching repercussions in terms of its capability to operate as an effective weapon system under adverse weatherconditions. The aircrew and majority of electronics depend on ECS to keep temperature, pressure and humidity levels within acceptable limits for efficient operation. These limits are explicitly defined in relevant MIL standards MIL-E-18927E(AS)[1]. In order to thoroughly analyze the ECS of under study aircraft[2, 3], Computational Fluid Dynamics (CFD) analysis techniques have been used. CFD techniques offer great flexibility since various conditions can be simulated and analyzed results can be used for required improvements in the system.

Neutronic Analysis of the European Sodium Fast Reactor: Part II - Burnup Results

2020 ◽  
Author(s):  
Emil Fridman ◽  
Francisco Álvarez Velarde ◽  
Pablo Romojaro Otero ◽  
Haileyesus Tsige-Tamirat ◽  
Antonio Jiménez-Carrascosa ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Core State ◽  
Computational Tools ◽  
Horizon 2020 ◽  
The Core ◽  
Continuous Energy ◽  
Sodium Fast Reactor ◽  
Computer Codes ◽  
Calibration And Verification

Abstract In the framework of the Horizon 2020 project ESFR-SMART (2017-2021), the European Sodium Fast Reactor (ESFR) core was updated through a safety-related modification and optimization of the core design from the earlier FP7 CP-ESFR project (2009-2013). This study is dedicated to neutronic analyses of the improved ESFR core design. The conducted work is reported in two parts. Part I deals with the evaluation of the safety-related neutronic parameters of the fresh Beginning-of-Life (BOL) core carried out by 8 organizations using both continuous energy Monte Carlo and deterministic computer codes. In addition to the neutronics characterization of the core, a special emphasis was put on the calibration and verification of the computational tools involved in the analyses. Part II is devoted to once-through and realistic batch-wise burnup calculations aiming at the establishing of the equilibrium core state, which will later serve as a basis for detailed safety analyses.

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

Characterization of seawater reverse osmosis fouled membranes from large scale commercial desalination plant

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Reverse Osmosis ◽  
Large Scale ◽  
Retention Rate ◽  
Local Level ◽  
Microscopic Analysis ◽  
Transmembrane Pressure ◽  
Hydraulic Permeability ◽  
Seawater Reverse Osmosis ◽  
A Chain

The objective of this work is to study the ageing state of a used reverse osmosis (RO) membrane taken in Algeria from the Benisaf Water Company seawater desalination unit. The study consists of an autopsy procedure used to perform a chain of analyses on a membrane sheet. Wear of the membrane is characterized by a degradation of its performance due to a significant increase in hydraulic permeability (25%) and pressure drop as well as a decrease in salt retention (10% to 30%). In most cases the effects of ageing are little or poorly known at the local level and global measurements such as (flux, transmembrane pressure, permeate flow, retention rate, etc.) do not allow characterization. Therefore, a used RO (reverse osmosis) membrane was selected at the site to perform the membrane autopsy tests. These tests make it possible to analyze and identify the cause as well as to understand the links between performance degradation observed at the macroscopic scale and at the scale at which ageing takes place. External and internal visual observations allow seeing the state of degradation. Microscopic analysis of the used membranes surface shows the importance of fouling. In addition, quantification and identification analyses determine a high fouling rate in the used membrane whose foulants is of inorganic and organic nature. Moreover, the analyses proved the presence of a biofilm composed of protein.

Characterization of Interconnect Defects Using Scanning Thermal Conductivity Microscopy

2004 ◽  
Author(s):  
H.W. Ho ◽  
J.C.H. Phang ◽  
A. Altes ◽  
L.J. Balk
Keyword(s):  
Thermal Conductivity ◽  
Integrated Circuits ◽  
Large Scale

Abstract In this paper, scanning thermal conductivity microscopy is used to characterize interconnect defects due to electromigration. Similar features are observed both in the temperature and thermal conductivity micrographs. The key advantage of the thermal conductivity mode is that specimen bias is not required. This is an important advantage for the characterization of defects in large scale integrated circuits. The thermal conductivity micrographs of extrusion, exposed and subsurface voids are presented and compared with the corresponding topography and temperature micrographs.

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