Admissibility Criteria for Propagating Phase Boundaries in a van der Waals Fluid.

1981 ◽  
Author(s):  
M. Slemrod
Keyword(s):  
Van Der Waals ◽  
Phase Boundaries ◽  
Van Der Waals Fluid

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.

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

Cosmological models constructed by van der Waals fluid approximation and volumetric expansion

2017 ◽  
Vol 14 (12) ◽  
pp. 1750183 ◽  
Author(s):  
G. C. Samanta ◽  
R. Myrzakulov
Keyword(s):  
Power Law ◽  
Van Der Waals ◽  
Rapid Expansion ◽  
Field Equations ◽  
Future Singularity ◽  
Fluid Approximation ◽  
Fluid Equation ◽  
Van Der Waals Fluid ◽  
Initial Epoch ◽  
The Universe

The universe modeled with van der Waals fluid approximation, where the van der Waals fluid equation of state contains a single parameter [Formula: see text]. Analytical solutions to the Einstein’s field equations are obtained by assuming the mean scale factor of the metric follows volumetric exponential and power-law expansions. The model describes a rapid expansion where the acceleration grows in an exponential way and the van der Waals fluid behaves like an inflation for an initial epoch of the universe. Also, the model describes that when time goes away the acceleration is positive, but it decreases to zero and the van der Waals fluid approximation behaves like a present accelerated phase of the universe. Finally, it is observed that the model contains a type-III future singularity for volumetric power-law expansion.

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