Stability of Subsonic Planar Phase Boundaries in a van der Waals Fluid

1999 ◽  
Vol 150 (1) ◽  
pp. 23-55 ◽  
Author(s):  
S. Benzoni-Gavage
Keyword(s):  
Van Der Waals ◽  
Phase Boundaries ◽  
Van Der Waals Fluid ◽  
Planar Phase

scholarly journals Mapping of the Temperature–Entropy Diagrams of van der Waals Fluids

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1519 ◽  
Author(s):  
Attila Imre ◽  
Réka Kustán ◽  
Axel Groniewsky
Keyword(s):  
Van Der Waals ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Model Material ◽  
Qualitative Description ◽  
Working Fluid ◽  
Expansion Phase ◽  
Van Der Waals Fluid ◽  
Characteristic Points ◽  
Reduced Temperature

The shape of the temperature vs. specific entropy diagram of a working fluid is very important to understanding the behavior of fluid during the expansion phase of the organic Rankine cycle or similar processes. Traditional wet-dry-isentropic classifications of these materials are not sufficient; several materials remain unclassified or misclassified, while materials listed in the same class might show crucial differences. A novel classification, based on the characteristic points of the T–s diagrams was introduced recently, listing eight different classes. In this paper, we present a map of these classes for a model material, namely, the van der Waals fluid in reduced temperature (i.e., reduced molecular degree of freedom) space; the latter quantity is related to the molar isochoric specific heat. Although van der Waals fluid cannot be used to predict material properties quantitatively, the model gives a very good and proper qualitative description. Using this map, some peculiarities related to T–s diagrams of working fluids can be understood.

scholarly journals Elastodynamic image forces on screw dislocations in the presence of phase boundaries

2017 ◽  
Vol 473 (2205) ◽  
pp. 20170484 ◽  
Author(s):  
Beñat Gurrutxaga-Lerma
Keyword(s):  
Screw Dislocation ◽  
Image Force ◽  
Planar Interface ◽  
Rigid Surface ◽  
Phase Boundaries ◽  
Unit Force ◽  
Screw Dislocations ◽  
Planar Phase ◽  
Explicit Formulae ◽  
Rigid Interface

The elastodynamic image forces acting on straight screw dislocations in the presence of planar phase boundaries are derived. Two separate dislocations are studied: (i) the injected, non-moving screw dislocation and (ii) the injected (or pre-existing), generally non-uniformly moving screw dislocation. The image forces are derived for both the case of a rigid surface and of a planar interface between two homogeneous, isotropic phases. The case of a rigid interface is shown to be solvable employing Head's image dislocation construction. The case of the elastodynamic image force due to an interface is solved by deriving the reflected wave's contribution to the global solution across the interface. This entails obtaining the fundamental solution (Green's function) for a point unit force via Cagniard's method, and then applying the convolution theorem for a screw dislocation modelled as a force distribution. Complete, explicit formulae are provided when available. It is shown that the elastodynamic image forces are generally affected by retardation effects, and that those acting on the moving dislocations display a dynamic magnification that exceed the attraction (or repulsion) predicted in classical elastostatic calculations.

Effect of critical fluctuations on adsorption of van der Waals fluid in a spherical cavity

2010 ◽  
Vol 48 (6) ◽  
pp. 810-827 ◽  
Author(s):  
Yongyi Peng ◽  
Hui Zou ◽  
Yuantao Xiang ◽  
Kechao Zhou ◽  
Xiaobin Li
Keyword(s):  
Spherical Cavity ◽  
Van Der Waals ◽  
Critical Fluctuations ◽  
Van Der Waals Fluid
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