bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvements in the Dehydration Process of Heavy Crude Oil, Using CFD: Case Study Campo Quifa-Colombia
Authors: Asuaje Tovar Miguel , Benítez Nelson , Quintero Dario , Gaviria Myriam R. , Díaz Eduardo , Chacón Carlos 
Published: October 2018

Quifa is one of the largest heavy-oil fields in Colombia with a total fluids production of 1,320 KBPD with a water cut of 96.7% through 272 active wells, approximatively. Facilities to handle such amounts of water, have to deliver crude oil under market specifications and clean up the water prior to its reinjection, require several stages of oil-water separation. The first phase in oil water separation process is Free Water Knock Out vessels (FWKO), which are in charge of extracting to extract most of the water, frequently assisted by heat or chemical products which help gravity to perform the separation. The treated water (which contain still some oil) is then directed to the following stage separation carried out by the big tanks called skimmers, which are designed to clean the water down to a few ppm of oil. Nowadays, even though the advance on computational calculations has increased, these tanks are frequently designed using only the concept of time of residence and considering the internal velocities to be as low as possible, so that improve separation. For these last considerations, FWKOs and Skimmers could have internal components like manifold or baffles.
The present work explains a CFD (Computational Fluids Dynamics) study of different internal manifolds configurations, which aimed to improve the fluid distributions and velocities inside the tanks of Quifa field. Simulations were performed by CFX commercial software under two-phase flow eulerian-eulerian homogeneous model.
The optimum manifold configuration, achieves uniform static pressure and flow distribution across the entire main pipe, reducing secondary internal flows and hydraulic losses.
Then, CFD calculations were carried out in the whole skimmer tank, using the original manifold and the improved one. Results show an increase in the separation process, due to the new internal velocity field.
Supported by the simulations results, these geometrical improvements in the internal manifolds were applied/constructed in one of the skimmer tanks in Quifa Field. Field results show an improvement on separation efficiency, going from 38% average efficiency in the original tanks (Skim-10 and Skim-30), up to 87% in the modified one (Skim-30). The quality of exit-water was reduced from 300 ppm average up to 77 ppm. The flow capacity of the skimmer 30 has been improved and can handle up to 600 KBFPD. This represents 62% more capacity than Skimmer 10, and 42% more than Skimmer 20.
Wind Flow Characteristics of a Model Downburst
Authors: Chowdhury Junayed , Chowdhury Jubayer , Parvu Dan , Karami Mohammad , Hangan Horia 
Published: October 2018

Downburst is an anti-tornado system with a slow rotating column of air slowly descending towards the ground which occurs due to the sudden downfall of air and precipitation generated from the cumulonimbus cloud. This natural event produces a strong downdraft which induces an outburst of damaging winds on or near the ground. This radially divergent wind with high velocity transpires when descending air strikes the ground which can cause immense damage to the ground mounted objects and structures.
This paper discusses the wind flow characteristics of downbursts produced in the Wind Engineering, Energy and Environment (WindEEE) Dome at Western University, Canada. Downdraft diameter and speed were varied to produce several downbursts like flow. Point measurements using Cobra probes and surface measurements using Particle Image Velocimetry (PIV) were performed to analyze the wind flow field in detail. Instantaneous downburst wind speeds were decomposed into slowly varying mean and residual fluctuations for different averaging time. Velocity profile with height from WindEEE was compared with previous experiments and full scale data.
Clogging Mechanisms of Vortex Pumps: Fibrous Material Motion Capture and Simulation With a CFD and DEM Coupling Method
Authors: Imasaka Yamato , Kanno Hitoshi , Saito Sumio , Miyagawa Kazuyoshi , Nohmi Motohiko , Isono Miho , Kawai Masahito 
Published: October 2018

Since wastewater pumps used in sewage systems have a trade-off relationship between non-clogging ability and efficiency, many internal flow and performance estimation studies so far have focused on optimizing both parameters. Here we focus on vortex pumps with a large space that allows foreign matters to pass through inside the casing that are used as sewage pumps.
In this paper, using experimental and numerical methods, we clarified clogging mechanism in the pumps using CFD (Computational Fluid Dynamics), Motion Capture and PIV (Particle Image Velocimetry) method.
Firstly, since it was difficult to observe the motion of foreign matter in the pumps, a simple experimental apparatus was built to quantify it. Five cylindrical rods were set in a rectangular water passage made of acrylic that has an 80mm*80mm cross section. The motion of strings in the passage was studied with experiments and computations. Strings were chosen as foreign matter because they are comparatively easy to compute and experiment with compared to fabric for example. In the experiments, the motion of strings could be recorded with a high-speed video camera and their motions were quantified with two-dimensional motion capture system.
In the computations, the motion of strings was simulated using DEM (Discrete Element Method) in the CFD software STAR-CCM+ by connecting particles with straight lines and coupling CFD with DEM. It is a numerical value method in which the motion and interaction of a large number of disintegrating objects is simulated. Its characteristic is that the point of contact between the particles is included in the equation of motion. Particles are connected by massless rods. These rods transmit force and momentum to each particle. Furthermore, the force between each particle is computed of the interaction between soft-particles and their bonding strength. In order to formulate the contact force between the particles, the spring-dashpot system is used. In addition, the optimal parameters of the DEM particles were obtained by conducting a parameter study.
We confirmed that the motion of the strings in the flow direction coincided with at a high precision in the passage. Furthermore, by applying the computational method with the above results, we were able to simulate the motion of strings in a vortex pump. We found that strings were pulled back into the pump by the backflow in the tongue of the pump. This backflow was observed using PIV results, providing experimental confirmation of this mechanism. Moreover, we were able to simulate the motions of fibrous materials in the passage and vortex pump.
Generation IV International Forum Education and Training Webinars: Education Tools for the Next Generation Workforce
Authors: Paviet Patricia 
Published: October 2018

The Gen IV International Forum (GIF) Education and Training Task Force was created to respond to the challenge of not only forming, training and/or retaining qualified Gen IV workforce but also educating and informing a more general public, policy makers on topics related to Gen IV reactor systems and cross-cutting subjects. The task force serves as a platform to enhance open education and training as well as communication and networking in support of GIF, and its objectives are to maintain the know-how in this field, to increase the knowledge of new advanced concepts, and to avoid the loss of the knowledge and competences that could seriously and adversely affect the future of nuclear energy.
While many countries are either ramping up or developing nuclear power production as an important step towards economic development and environmental protection, a decrease or uncertainty of the fiscal year budgets have left organizations and agencies looking for new avenues for training and educating a qualified workforce. This has led to an increase in those looking for readily available education and training resources.
Using modern internet technologies, the GIF Education and Training Task Force has launched a webinar series on Gen IV systems in September 2016, which is accessible to a broad audience and is educating and strengthening the knowledge of participants in applications to advanced reactors. This achievement is the direct result of partnering with university professors and subject matter experts who conduct live webinars on a monthly basis. The live webinars are recorded and archived as an online educational resource to the public from the GIF website (www.gen-4.org). In addition, the webinars offer unprecedented opportunities for interdisciplinary crosslinking and collaboration in education and research. The GIF webinars, with their expansion of topics, targets a large spectrum of those that do not know but are desiring to learn about the many aspects of advanced reactor systems. The details and examples of the GIF webinar modules will be presented in our paper.
Nonlinear Analysis in Pressure Vessel Design Codes: Recommendations for Codified Rules Improvements
Authors: Faidy Claude 
Published: October 2018

During the past 30 years the main rules to design pressure vessels were based on elastic analyses. Many conservatisms associated to these different elastic approaches are discussed in this paper, like: stress criteria linearization for 3-D components, stress classification in nozzle areas, plastic shake down analysis, fatigue analysis, Ke evaluation, and pipe stress criteria for elastic follow-up due to thermal expansion or seismic loads...
This paper will improve existing codified rules in nuclear and non-nuclear Codes that are proposed as alternatives to elastic evaluation for different failure modes and degradation mechanisms: plastic collapse, plastic instability, tri-axial local failure, rupture of cracked component, fatigue and Ke, plastic shakedown. These methods are based on limit loads, monotonic or cyclic elastic-plastic analyses.
Concerned components are mainly vessels and piping systems.
No existing Code is sufficiently detailed to be easily applied; the needs are stress analysis methods through finite elements, material properties including material constitutive equations and criteria associated to each methods and each failure modes.
A first set of recommendation to perform these inelastic analysis will be presented to improve existing codes on an international harmonized way, associated to all material properties and criteria needed to apply these modern methods. An international draft Code Case is in preparation.
RCIC Turbo-Pump Scaling Through CFD and Model Testing for the Texas A&M University NHTS Facility
Authors: Hawila Mohammad A. , Kirkland Karen Vierow 
Published: October 2018

One of the requirements for licensing a nuclear power plant in the U.S is the capability to survive and recover from a station blackout according to the U.S Nuclear Regulatory Commission (USNRC). Station blackout is the loss of all off-site and onsite power simultaneously. Therefore, experimental test facilities are being constructed and operated to test the performance of the related safety systems in a nuclear power plant. Design and construction of a test facility creates the need to perform scaling analysis to ensure proper representation of key components and phenomena of interest. One of the main outcomes of the scaling analysis is the quantitative estimation of the Similarity Level (SL), which requires derivation of dimensionless scaling parameters and prediction of appropriate input values for the scaling parameters.
To study the performance of the Reactor Core Isolation Cooling (RCIC) system, the Nuclear Heat Transfer Systems (NHTS) Laboratory at Texas A&M University has constructed and is operating a RCIC test facility. This paper presents the scaling analysis with reference to a full-size RCIC system and the RCIC system turbine was used as the main component for scaling. The input parameters for dimensionless scaling parameters were obtained through experimental measurements and CFD analysis. The CFD analysis is for the ZS-1 RCIC system turbine model. The STAR-CCM+ CFD code was used in this study to create and run simulations for steady state normal and abnormal operating conditions for the NHTS-developed CAD models.
The input for the dimensionless scaling parameters was estimated. Input parameters were collected both experimentally and from CFD simulations and inserted into these equations. As a result, a high degree of similarity was confirmed, with a minimum of 82% between the NHTS and full-size RCIC systems. The 82% represents the amount of transfer properties conserved between the two systems. Consequently, this high similarity level allows the NHTS RCIC system to be used to study the behavior of the full-size RCIC system under Beyond Design Bases Accident (BDBA) conditions.
Future work is to study and model other components of the RCIC system such as the suppression chamber to estimate similarity levels and study their effects on behavior of the system under BDBA.
A Structural Integrity Assessment of a Nuclear Boiler Superheater Bifurcation at High Temperature
Authors: Nadri Brahim , Wang Robert X. 
Published: October 2018

Steam generating boilers in gas cooled nuclear reactors in the UK operate at high temperatures and some of them have been in service for more than 30 years and are now facing the challenges from long term operation extension demand. The tubular components experience surface metal losses due to exposure to oxidation and corrosive environment and as a result, some tubes suffer from restricted flow which may lead to an increased creep-fatigue crack initiation damage. To maintain or recover boiler heat transfer efficiency, internal chemical cleaning of selected boiler tubes is carried out, which introduces additional metal loss in the tube wall, weakening its load bearing capacity.
Some boiler components are subject to high temperature, pressure and mechanical loadings in large number of operating cycles through life, introducing creep in addition to cyclic fatigue damage.
In support of an operational safety case and plant long term operation extension requirements, structural integrity assessments have been carried out on a critical boiler component — bifurcation, taking into account tube wall metal loss for extended long term services, including the effects of possible future chemical cleaning operations.
This paper presents the finite element analyses and R5 Volume 2/3 assessment work carried out for the structural integrity substantiation of a stainless steel boiler tube bifurcation. The bifurcation is a tubular component subject to significant applied displacement due to long range thermal expansion of the neighbouring components. The initial study following normal industry practice using a decoupled analysis approach showed that the strain ranges obtained would exceed the creep-fatigue crack initiation capacity and plastic ratchetting would occur which would lead to short term, incremental plastic collapse, hence a safety case could not be made.
To meet the challenge, the analysis and assessment processes have been examined. A coupled FE analysis approach was used to remove the pessimism associated with the decoupled analysis approach. This approach captures the displacement-controlled nature of the system loads and allows a more realistic assessment. In addition, the plant life has been divided into a number of assessment periods such that the more realistic metal loss appropriate for each period could be used. Furthermore, segregated temperature zones have been considered in the assessment, leading to a significant reduction in the creep-fatigue crack initiation damage and a satisfactory extended long term operation safety case.
Post-Test CFD Analysis of Non-Uniformly Heated 19-Pin Fuel Bundle Cooled by HLM
Authors: Marinari R. , Di Piazza I. , Angelucci M. , Martelli D. 
Published: October 2018

In the context of the studies on GEN. IV/ADS nuclear systems, the correct evaluations of the temperature distribution in the fuel pin bundle is of central interest. In particular, the use of lead or lead-bismuth eutectic (LBE) as coolant for the new generation fast reactors is one of the most promising choices. Due to the high density and high conductivity of lead or LBE, a detailed analysis of the thermo-fluid dynamic behavior of the heavy liquid metal (HLM) inside the sub-channels of a fuel rod bundle is necessary in order to support the Front-End Engineering Design (FEED) of GEN. IV/ADS prototypes and demonstrators. In this frame, the synergy between numerical analysis by CFD and data coming from large experimental facilities seems to be crucial to assess the feasibility of the components.
At ENEA-Brasimone R.C., large experimental facilities exist to study HLM free, forced and mixed convection in loops and pools: e.g. NACIE-UP is a large scale LBE loop for mixed convection experiments. The MYRRHA-19 like Fuel Pin Bundle Simulator installed in the NACIE-UP facility allows to make non-uniform and dissymmetric tests with only a few pins heated. This technical feature of the FPS is very interesting for CFD validation and this kind of data tests in HLM fuel bundles are not so common in the literature.
In the present paper, a post-test validation is made by a detailed CFD model of the test section. Experimental data, statistically treated by the error propagation theory, are briefly presented and a preliminary comparison with CFD results using different models/turbulent Prandtl numbers are shown. Three monitored section at different levels are compared both for wall and bulk temperatures. This post-test comparison with this experimental configuration is unique and represents a further step towards the validation of the CFD models and methods in fuel bundle geometries cooled by HLM.
Geometry Survey on the Convex Shaped Core for Recriticality Prevention Against CDA in Sodium-Cooled Fast Reactor
Authors: Chitose Keiko , Tachi Yoshiaki , Wakabayashi Toshio , Takaki Naoyuki 
Published: October 2018

In sodium-cooled fast reactors, the core is not arranged in its most reactive configuration. In this case, when the fuel melts to form a molten pool, the recriticality may occur by positive reactivity insertion due to core compaction. To prevent such recriticality, special devices of the fuel subassembly structure for discharging the molten fuel from the core region, have been investigated by the Japan Atomic Energy Agency (JAEA). On the other hand, the inherent feature of core geometry and the neutron characteristics may provide the similar effect to prevent such recriticality. The purpose of this study is to design the core specification its deformation in CDA causes negative feedback to subcritical condition, without any fuel discharge device.
The convex shaped core has the longer fuel length in the inner-core region and the shorter fuel in the outer-core region. Therefore, the core geometry as intact status has a lower neutron leakage effect. When the fuel melts in CDA, the core height is compacted and negative reactivity insertion is expected during molten pool formation. The convex shaped core is based on the large-scale cylindrical homogeneous core (3,600 MWth, 4.95m in core diameter, and 0.75m in core height). The calculation showed that the compaction of cylindrical core leads to a reactivity gain, whereas the convex shaped core results in negative reactivity effect.
In this geometry, both inner-core and outer-core are divided into two regions. Furthermore, we introduced the smaller diameter pin for inner-core and keep uniform Pu enrichment for all regions. The smaller diameter pins in high importance region are effective for flat-distribution. Through pin diameter survey, we confirmed the advantages of smaller diameter pin, such as reducing pressure loss of core coolant and decreasing the height of molten pool.
Experimental Study of Aerosol Behavior During Pool Scrubbing: Part 1 — Visualization Measurement of Aerosol Particle in a Single Rising Bubble
Authors: Fujiwara Kota , Kikuchi Wataru , Nakamura Yuki , Saito Shimpei , Yuasa Tomohisa , Kaneko Akiko , Abe Yutaka 
Published: October 2018

As pool scrubbing plays an important role in fission product (FP) decontamination, a reliable model is needed. Despite the needs, mechanism of FP transfer from air-water from the swarm is not explained exactly which means that the evaluation of physical model used in pre-existing model couldn’t be done enough.
Existing model for pool scrubbing is predicted in the MELCOR code. Inside the code, a simple model of bubbly jet divided in 3 regions is used: 1) Globule region where the gas including FP enter and collapse, 2) Swarm rise region where the bubble rises up stationary after the collapse is done and, 3) Entrainment region where the bubble pop out to the atmosphere. In each region, the decontamination factor (DF), the particle density ratio before and after each region, is calculated. On these region, flow and physical force inside the gas phase is predicted to be one of the driving force which cause the FP transfer.
Therefore, our study aims at the particle behavior on the gas phase. As to understand the physical phenomenon individually, the study focuses on flow behavior and inner flow of a single rising bubble. As an approach, comparison of bubble containing aerosol and no aerosol has been done for each parameter of size, aspect ratio, velocity. Compared with existing equations, the rising speed of clean bubble condition and aspect ratio of CSI condition agreed well to the MELCOR code [1]. On the other hand, many difference were also measured in other condition.
Application of parameters obtained from experiment were done against the MELCOR model. Calculation of velocity inside the oil droplet using the experimental parameters obtained from visualization measurement was done. The local gravitational sedimentation and centrifugal velocity took a higher value in clean bubble and OX50 condition compared to CSI condition. On the other hand, Brownian diffusion velocity had an opposite trend. PIV measurement were performed by a silicone oil to visualize the inner flow clearly and compared with the calculation. Seen from the results, the local diffusion velocity took a lower value compared to the calculation using the MELCOR model.
Blind Simulations of NACIE-UP Experimental Tests by STH Codes
Authors: Forgione Nicola , Angelucci Morena , Barone Gianluca , Polidori Massimiliano , Cervone Antonio , Di Piazza Ivan , Giannetti Fabio , Lorusso Pierdomenico , Hollands Thorsten , Papukchiev Angel 
Published: October 2018

In the frame of the SESAME project, a benchmarking activity was proposed to validate the existing system thermal-hydraulics codes for Heavy Liquid Metal reactors. More specifically, blind simulations on three well-defined experiments were carried out on the NACIE-UP facility, using CATHARE by ENEA, ATHLET by GRS, RELAP5-3D by University of Roma and RELAP5/Mod3.3 by University of Pisa. The numerical models were calibrated in terms of system thermal losses and gas enhanced circulation by means of the outcomes from specific experimental preliminary tests.
The present discussion expose, compare and analyze the numerical results of some representative parameters (primary lead-bismuth eutectic (LBE) mass flow rate, temperatures and pressure) charaterizing the system behaviour in transiet scenarios in a “pre-test” blind numerical assessment.