Corrosion/Precipitation in Non-Isothermal Lead Alloy Coolant Systems

2006 ◽  
Author(s):  
Taide Tan ◽  
Yitung Chen ◽  
Huajun Chen ◽  
Hsuan-Tsung Hsieh
Keyword(s):  
Kinetic Model ◽  
Analytical Solutions ◽  
Numerical Models ◽  
National Laboratory ◽  
Precipitation Rate ◽  
Lead Alloy ◽  
Bulk Concentration ◽  
Delta Set ◽  
Test Loop ◽  
Set Up

A kinetic model was developed to investigate the corrosion and precipitation in non-isothermal lead alloy coolant systems. By considering a turbulent core region and a laminar sub-layer, analytical solutions of the mass transfer equations in both regions were obtained. The analytical expressions of both the local corrosion/ precipitation rate and the bulk concentration were obtained from the present kinetic model. Numerical models were also developed for simulating the corrosion and precipitation in non-isothermal Lead alloy pipe/loop systems and the results were compared with the analytical solutions. By applying this model to a test loop named "DELTA" set up at the Los Alamos National Laboratory the present study illustrates systematically dependence of the corrosion/precipitation rate and bulk concentration on the axial temperature profile and other hydraulic factors. The results were compared with the available experimental data.

scholarly journals Application of Artificial Neural Networks for Predicting the Bearing Capacity of Shallow Foundations on Rock Masses

2021 ◽  
Author(s):  
M. A. Millán ◽  
R. Galindo ◽  
A. Alencar
Keyword(s):  
Bearing Capacity ◽  
Analytical Solutions ◽  
Shear Failure ◽  
Numerical Models ◽  
Computational Effort ◽  
Shallow Foundations ◽  
Geological Strength Index ◽  
Rock Masses ◽  
Ann Model ◽  
Artificial Neural

AbstractCalculation of the bearing capacity of shallow foundations on rock masses is usually addressed either using empirical equations, analytical solutions, or numerical models. While the empirical laws are limited to the particular conditions and local geology of the data and the application of analytical solutions is complex and limited by its simplified assumptions, numerical models offer a reliable solution for the task but require more computational effort. This research presents an artificial neural network (ANN) solution to predict the bearing capacity due to general shear failure more simply and straightforwardly, obtained from FLAC numerical calculations based on the Hoek and Brown criterion, reproducing more realistic configurations than those offered by empirical or analytical solutions. The inputs included in the proposed ANN are rock type, uniaxial compressive strength, geological strength index, foundation width, dilatancy, bidimensional or axisymmetric problem, the roughness of the foundation-rock contact, and consideration or not of the self-weight of the rock mass. The predictions from the ANN model are in very good agreement with the numerical results, proving that it can be successfully employed to provide a very accurate assessment of the bearing capacity in a simpler and more accessible way than the existing methods.

Study on the working state of the five hundred-meter aperture spherical telescope using step-wise assignment method

2014 ◽  
Vol 229 (2) ◽  
pp. 316-324 ◽  
Author(s):  
Yu Liu ◽  
Feng Gao
Keyword(s):  
Nonlinear Equations ◽  
Analytical Solutions ◽  
Driving Mechanism ◽  
Initial Value ◽  
Unknown Parameters ◽  
Support Structure ◽  
Assignment Method ◽  
New Type ◽  
Set Up ◽  
The Mathematical Model

The working state of the five hundred-meter aperture spherical telescope (FAST) is solved using the step-wise assignment method. In this paper, the mathematical model of the cable-net support structure of the FAST is set up by the catenary equation. There are a large number of nonlinear equations and unknown parameters of the model. The nonlinear equations are solved by using the step-wise assignment method. The method is using the analytical solutions of the cable-net equations of one working state as the initial value for the next working state, from which the analytical solutions of the nonlinear equations of the cable-net for each working state of the FAST and the tension and length of each driving cable can be obtained. The suggested algorithm is quite practically well suited to study the working state of the cable-net structures of the FAST. Also, the working state analysis result of the cable-net support structure of a reduced model of the cable-net structure reflector for the FAST is given to verify the reliability of the method. In order to show the validity of the method, comparisons with another algorithm to set the initial value are presented. This method has an important guiding significance to the further study on the control of the new type of flexible cable driving mechanism, especially the FAST.

scholarly journals Kelvin wave hydraulic control induced by interactions between vortices and topography

2011 ◽  
Vol 687 ◽  
pp. 194-208 ◽  
Author(s):  
Andrew McC. Hogg ◽  
William K. Dewar ◽  
Pavel Berloff ◽  
Marshall L. Ward
Keyword(s):  
Shallow Water ◽  
Analytical Solutions ◽  
Critical Condition ◽  
Numerical Models ◽  
Kelvin Waves ◽  
Water Model ◽  
Hydraulic Jumps ◽  
Hydraulic Control ◽  
Kelvin Wave ◽  
Shallow Water Model

AbstractThe interaction of a dipolar vortex with topography is examined using a combination of analytical solutions and idealized numerical models. It is shown that an anticyclonic vortex may generate along-topography flow with sufficient speeds to excite hydraulic control with respect to local Kelvin waves. A critical condition for Kelvin wave hydraulic control is found for the simplest case of a 1.5-layer shallow water model. It is proposed that in the continuously stratified case this mechanism may allow an interaction between low mode vortices and higher mode Kelvin waves, thereby generating rapidly converging isopycnals and hydraulic jumps. Thus, Kelvin wave hydraulic control may contribute to the flux of energy from mesoscale to smaller, unbalanced, scales of motion in the ocean.

Leakage Flow Investigations on a Through-Wall Crack Related to Thermal Fatigue of Nuclear Power Plant Piping

2017 ◽  
Author(s):  
Stefan Schmid ◽  
Rudi Kulenovic ◽  
Eckart Laurien
Keyword(s):  
Experimental Data ◽  
Nuclear Power ◽  
Numerical Models ◽  
Measurement Techniques ◽  
Experimental Investigations ◽  
Leakage Flow ◽  
Test Rig ◽  
Reduced Pressure ◽  
Flow Rates ◽  
Set Up

For the validation of empirical models to calculate leakage flow rates in through-wall cracks of piping, reliable experimental data are essential. In this context, the Leakage Flow (LF) test rig was built up at the IKE for measurements of leakage flow rates with reduced pressure (maximum 1 MPA) and temperature (maximum 170 °C) compared to real plant conditions. The design of the test rig enables experimental investigations of through-wall cracks with different geometries and orientations by means of circular blank sheets with integrated cracks which are installed in the tubular test section of the test rig. In the paper, the experimental LF set-up and used measurement techniques are explained in detail. Furthermore, first leakage flow measurement results for one through-wall crack geometry and different imposed fluid pressures at ambient temperature conditions are presented and discussed. As an additional aspect the experimental data are used for the determination of the flow resistance of the investigated leak channel. Finally, the experimental results are compared with numerical results of WinLeck calculations to prove specifically in WinLeck implemented numerical models.

scholarly journals TRUEX Processing of Plutonium Analytical Solutions at Argonne National Laboratory

1997 ◽  
Vol 32 (1-4) ◽  
pp. 303-326 ◽  
Author(s):  
David B. Chamberlain ◽  
Cliff Conner ◽  
Joseph C. Hutter ◽  
Ralph A. Leonard ◽  
David G. Wygmans ◽  
...  
Keyword(s):  
Analytical Solutions ◽  
National Laboratory ◽  
Argonne National Laboratory

scholarly journals On the interpretation of annual oscillations in 32Si and 36Cl decay rate measurements

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Pommé ◽  
K. Pelczar ◽  
K. Kossert ◽  
I. Kajan
Keyword(s):  
Decay Rate ◽  
Solar Neutrino ◽  
National Laboratory ◽  
Neutrino Flux ◽  
Measurement Data ◽  
Brookhaven National Laboratory ◽  
Decay Rates ◽  
Dew Point ◽  
Annual Variations ◽  
Set Up

AbstractThe 32Si decay rate measurement data of Alburger et al. obtained in 1982–1986 at Brookhaven National Laboratory have been presented repeatedly as evidence for solar neutrino-induced beta decay. The count rates show an annual sinusoidal oscillation of about 0.1% amplitude and maximum at February–March. Several authors have claimed that the annual oscillations could not be explained by environmental influences on the set-up, and they questioned the invariability of the decay constant. They hypothesised a correlation with changes in the solar neutrino flux due to annual variations in the Earth-Sun distance, in spite of an obvious mismatch in amplitude and phase. In this work, environmental conditions at the time of the experiment are presented. The 32Si decay rate measurements appear to be inversely correlated with the dew point in a nearby weather station. Susceptibility of the detection set-up to local temperature and humidity conditions is a likely cause of the observed instabilities in the measured decay rates. Similar conclusions apply to 36Cl decay rates measured at Ohio State University in 2005–2012.

Assessment of Radius of Investigation of Pressure Transient Analysis in Highly Heterogeneous Reservoirs

2021 ◽  
Author(s):  
Murat Zeybek ◽  
Lei Jiang ◽  
Hadrien Dumont
Keyword(s):  
Transient Analysis ◽  
Numerical Models ◽  
Heterogeneous Systems ◽  
Layered Systems ◽  
Pressure Transient ◽  
Heterogeneous Reservoirs ◽  
Geological Features ◽  
Heterogeneous Formations ◽  
Set Up ◽  
New Generation

Abstract The radius of investigation (ROI) of pressure transient analyses has been traditionally assessed using analytical formulations with basic reservoir parameters for homogenous systems. Numerous studies aimed to improve ROI formulations to incorporate all reservoir and testing parameters such as gauge resolution and rate for more accurate ROI assessments. However, new generation wireline formation testers aim to improve deep transient tests with significant developments in gauge resolution and increasing rate. Challenges still remain in heterogeneous formations such as shaly sands and carbonate reservoirs. In this study, detailed conceptual high-resolution numerical models are set up, including comprehensive reservoir and measurement parameters, to investigate more realistic ROI assessments in layered heterogeneous systems without and with hydraulic communication. Several conceptual examples are presented in layered systems with permeability contrasts. In addition, deviation from infinite-acting radial flow (IAFR) and pressure propagation in highly heterogeneous layered systems are investigated to detect the presence of geological features, including closed boundary systems and the presence of a fault in the proximity of wellbore.

scholarly journals A NEW HYBRID APPROACH IN THE CALIBRATION OF BOUSSINESQ-TYPE WAVE BREAKING MODELS

2018 ◽  
pp. 24
Author(s):  
Joaquín Moris ◽  
Patricio Catalán ◽  
Rodrigo Cienfuegos
Keyword(s):  
Wave Height ◽  
Wave Breaking ◽  
Numerical Models ◽  
Hybrid Approach ◽  
Boussinesq Equations ◽  
Water Levels ◽  
Statistical Parameters ◽  
Time Space ◽  
Forcing Mechanisms ◽  
Set Up

Wave breaking is one of the main forcing mechanisms in coastal hydrodynamics, driving mean water levels and currents. Understanding its behavior is key in the goal of improving our comprehension of coastal morphodynamics variations. One way to improve our understanding is through the use of numerical models, such as phase-resolving numerical models based on the Boussinesq equations (Kirby, 2016), which are modified to include breaking by the inclusion of a breaking criteria and a dissipation mechanism. Since there is not a universal law capable of characterizing the wave breaking, the existing models must be calibrated. Traditionally, this is done by adjusting wave height profiles and other free surface statistical parameters without explicitly considering the time-space location and duration of the breaking process. Consequently, it is possible to calibrate a model that accurately represents wave elevation statistics parameters, such as wave height and wave set-up; however, it might not necessarily represent the breaking location-duration and therefore, the forcing.

Use of Tracer Particles for Tracking Fluid Interfaces in Primary Cementing

2019 ◽  
Author(s):  
Amir Taheri ◽  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Bjørnar Lund ◽  
Alexandre Lavrov ◽  
...  
Keyword(s):  
Numerical Models ◽  
Secondary Flows ◽  
Equivalent Model ◽  
Fluid Interfaces ◽  
Element Analysis ◽  
Two Fluids ◽  
Tracer Particles ◽  
Narrow Side ◽  
Primary Cementing ◽  
Set Up

Abstract In this study, a new approach for detailed tracking of the interface between well fluid and cement by using particles is investigated. This can improve the quality of annular cementing of CO2 wells and thus the storage safety. For this purpose, the displacement mechanisms of Newtonian and non-Newtonian fluids in the annulus of vertical and inclined wells is investigated by using an experimental set-up with an eccentric annular geometry and by finite element analysis of an equivalent model with COMSOL Multiphysics solver. For more efficient displacement, the displacing fluid has a higher density than the displaced fluid, and the intermediate-buoyancy particles that reside at the interface between successive fluids are introduced into the models. Such particles must overcome strong secondary flows in order to travel with the interface. Particle motions are investigated in different experimental and numerical models, and their effectiveness is investigated. The experimental results confirm that while the particles with a size of 425–500 um are unable to overcome the secondary flows in eccentric vertical models and track the interface, they can be useful for tracking the interface between two fluids in an eccentric model with a small inclination to the narrow side. CFD analysis investigates this behavior with more details and shows the effects of some parameters on the particle motions.

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