Straight Edge Dislocation in a Thin Two-Phase Plate, II. Impurity-Vacancy Polarization of Plate, Interaction of a Dislocation with Interface and Free Surfaces

1992 ◽  
Vol 129 (2) ◽  
pp. 363-377 ◽  
Author(s):  
M. Yu. Gutkin ◽  
A. E. Romanov
Keyword(s):  
Edge Dislocation ◽  
Straight Edge ◽  
Phase Plate ◽  
Two Phase ◽  
Free Surfaces

Threading Screw Dislocations in a Two-Phase Plate and a Two-Phase Sphere

2018 ◽  
Vol 55 (1) ◽  
pp. 102-116 ◽  
Author(s):  
A.L. Kolesnikova ◽  
M.Yu. Gutkin ◽  
A.E. Romanov
Keyword(s):  
Screw Dislocation ◽  
Hollow Sphere ◽  
Phase Plate ◽  
Stress Distributions ◽  
Two Phase ◽  
Parallel Edge ◽  
Free Surfaces ◽  
Shear Moduli ◽  
Elastic Fields ◽  
First Time

Abstract A screw dislocation perpendicular to free surfaces and an interface in a two-phase plate, and a screw dislocation piercing a two-phase hollow sphere are considered. The analytical solutions of the boundary-value problems have been found for the first time with the help of the virtual defects technique. Elastic fields of the screw dislocation in the plate are presented in the form of integrals with Bessel functions. Elastic fields of the screw dislocation in the hollow sphere have the form of series with Legendre polynomials. Stress distributions in both of the considered geometries are plotted. The influence of the geometric parameters of the considered solids and the ratio of the shear moduli on the stresses is analyzed. The interaction of a screw dislocation with a parallel edge dislocation is discussed.

An Edge Dislocation in a Three-Phase Composite Cylinder Model

1991 ◽  
Vol 58 (1) ◽  
pp. 75-86 ◽  
Author(s):  
H. A. Luo ◽  
Y. Chen
Keyword(s):  
Edge Dislocation ◽  
Stable Equilibrium ◽  
Phase Model ◽  
Composite Cylinder ◽  
Two Phase ◽  
Trapping Mechanism ◽  
Three Phase ◽  
Cylinder Model ◽  
Stable Equilibrium Position ◽  
The Stability

An exact solution is given for the stress field due to an edge dislocation embedded in a three-phase composite cylinder. The force on the dislocation is then derived, from which a set of simple approximate formulae is also suggested. It is shown that, in comparison with the two-phase model adopted by Dundurs and Mura (1964), the three-phase model allows the dislocation to have a stable equilibrium position under much less stringent combinations of the material constants. As a result, the so-called trapping mechanism of dislocations is more likely to take place in the three-phase model. Also, the analysis and calculation show that in the three-phase model the orientation of Burgers vector has only limited influence on the stability of dislocation. This behavior is pronouncedly different from that predicted by the two-phase model.

Modeling Separation and Cavitation Behind a Blunt Body

2016 ◽  
Author(s):  
Jingsen Ma ◽  
Chao-Tsung Hsiao ◽  
Xiongjun Wu ◽  
Georges L. Chahine
Keyword(s):  
Blunt Body ◽  
Ambient Pressure ◽  
Separated Flow ◽  
The Body ◽  
Large Cavity ◽  
Cavitation Flow ◽  
Two Phase ◽  
Free Surfaces ◽  
Number Flow ◽  
Transition Scheme

Cavitation flow behind a blunt body is modeled using a physics-based numerical model of cavitation initiation and transition to larger cavities. The calculations initiate from the dynamics of nuclei, then tracks the dispersed bubble phase with a two-phase viscous model. This solver includes a level set method to model coalescence of the nuclei into large cavities and to track the dynamics of the resulting free surfaces. A transition scheme enables collection of the bubbles into a large cavity and also enables breakup of a large cavity into a bubble cloud. Using this model, simulations are conducted for different flow velocities and corresponding cavitation regimes. When the velocity is relatively small (i.e., large cavitation number), flow separation behind the body results in the shedding of vortices, which capture nuclei in their cores to form elongated vortical cavities. As the flow velocity increases (or as the ambient pressure decreases) the flow evolves into a separated flow with a large cavity behind the body. A reentrant jet may form and move upstream into the cavity towards the body. This jet periodically shears off portions of the cavity volume, resulting in large amounts of bubble clouds. These results are in good qualitative agreements with experimental observations.

Two-phase plate-fin heat exchanger modeling for waste heat recovery systems in diesel engines

2014 ◽  
Vol 133 ◽  
pp. 183-196 ◽  
Author(s):  
Emanuel Feru ◽  
Bram de Jager ◽  
Frank Willems ◽  
Maarten Steinbuch
Keyword(s):  
Heat Exchanger ◽  
Diesel Engines ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Phase Plate ◽  
Two Phase

A Two-Phase CFD Approach to the PTS Problem Evaluated on COSI Experiment

2008 ◽  
Author(s):  
Pierre Coste ◽  
Je´roˆme Pouvreau ◽  
Je´roˆme Lavie´ville ◽  
Marc Boucker
Keyword(s):  
Computational Domain ◽  
Two Phase ◽  
Free Surfaces ◽  
Interface Reconstruction ◽  
Pressurized Thermal Shock ◽  
Hydraulic Conditions ◽  
Reasonable Range ◽  
Safety Studies ◽  
Core Cooling ◽  
Contact Condensation

The study is done in the context of Pressurized Thermal Shock (PTS) CFD investigations related to PWR life duration safety studies. In the simulations of such situations direct contact condensation on free surfaces much larger than cells size is a key phenomenon. Those large interfaces require a special full set of models which has been recently implemented in the NEPTUNE_CFD code. Out of large interfaces regions, some dispersed or churn flows can take place. Both situations can be taken into account in the computational domain. The approach includes an interface recognition but not an interface reconstruction. It is evaluated on COSI experiment. COSI facility is scaled 1/100 for volume and power from a 900 MW PWR under LOCA thermal hydraulic conditions. Measurements include temperature profiles at various axial positions in the pipe. The paper focuses on one test corresponding to a situation with a low water level in the leg. It is a demanding case for two-phase CFD because -a- the liquid layer which is of prime importance in PTS studies can be quite thin in comparison with the whole computational domain -b- the emergency core cooling jet plays an important role. Results are within a reasonable range even with a coarse mesh. Calculations with finer meshes quantify the effect of a better simulation of the jet fall and impact on the wall.

A Comparison of the Surface Composition of Solid and Liquid Alloys

1986 ◽  
Vol 83 ◽  
Author(s):  
J. A. Barnard ◽  
P. Wynblatt ◽  
William C. Johnson ◽  
W.W. Mullins
Keyword(s):  
Liquidus Temperature ◽  
Surface Composition ◽  
Solute Segregation ◽  
Two Phase ◽  
Free Surfaces ◽  
Scanning Auger Microprobe ◽  
Liquid States ◽  
Solid Liquid ◽  
Solid And Liquid States

ABSTRACTThe surface compositions of three In-Pb alloys (1.42a/o Pb, 3.07a/o Pb, and 5.86a/o Pb) have been obtained as a function of temperature in both solid and liquid states using a scanning Auger microprobe. All data were obtained at temperature, from equilibrated samples in a region of about fifty degrees on either side of the liquidus temperature. Lead was found to be the segregating component in all cases. From these measurements, the heat of segregation has been calculated for all alloys in both states. In each alloy the magnitude of the heat of segregation declines significantly on melting although the absolute surface compositions are found to be continuous across the two phase solid-liquid field. These results are interpreted in the light of current segregation theories. Particular attention is paid to the role of elastic effects on solute segregation to free surfaces.

scholarly journals Computation of effective free surfaces in two phase flows

2012 ◽  
Vol 24 (8) ◽  
pp. 087101 ◽  
Author(s):  
R. Yapalparvi ◽  
B. Protas
Keyword(s):  
Two Phase Flows ◽  
Two Phase ◽  
Free Surfaces

Simulation of Oscillating Free Interface Behavior by Using OpenFOAM

2013 ◽  
Author(s):  
Qingyun Zeng ◽  
Jiejin Cai ◽  
Tadashi Watanabe
Keyword(s):  
Flow Field ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Moving Grid ◽  
Arbitrary Lagrangian Eulerian ◽  
Local Pressure ◽  
Two Phase ◽  
Free Surfaces ◽  
Free Interface ◽  
Liquid Phases

The motions of free interface and its coupling with bubble in oscillating two-phase flow field are simulated numerically by using OpenFOAM. The oscillating two-phase flow field is simulated using the VOF method and the moving grid of the Arbitrary Lagrangian-Eulerian (ALE) method. Firstly, free interface is simulated, and its interface elevation is well coincided with experimental results. Then simulations of free faces with or without bubble near it under oscillating condition are compared. It is found that the free interface between gas and liquid phases is affected largely by the oscillation, and the effect is intensified when bubble is near free surfaces. And local pressure disturbance is found after bubble coalesces with free interface.

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