scholarly journals Symmetry Properties of Reciprocity Relations and Conditions for Minimum Entropy Production Law (In)validity

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Marian Štrunc ◽  
Milena Kheilová
Keyword(s):  
Entropy Production ◽  
Minimum Entropy ◽  
Minimum Entropy Production ◽  
Reciprocity Relations ◽  
Symmetry Properties ◽  
Kinetic Coefficients ◽  
Symmetry Requirement

Consequences of symmetry properties of the phenomenological kinetic coefficients in Onsager-Casimir reciprocity relations for the minimum entropy production law validity are studied. The usually accepted symmetry requirement of the all cross kinetic coefficients for the validity of this law is found to be too strict.

scholarly journals New look at an old principle: an alternative formulation of the theorem of minimum entropy production

2019 ◽  
Vol 16 (1) ◽  
pp. 508-517
Author(s):  
Gyula Vincze ◽  
Andras Szasz
Keyword(s):  
Entropy Production ◽  
Constitutive Equations ◽  
Diffusion Tensor ◽  
Axial Vector ◽  
Initial Time ◽  
Variation Principle ◽  
Minimum Entropy ◽  
Dissipation Potential ◽  
Minimum Entropy Production ◽  
Reciprocity Relations

We formulate a direct generalization of the Prigogine’s principle of minimum entropy production, according to a new isoperimetric variation principle by classical non-equilibrium thermodynamics. We focus our attention on the possible mathematical forms of constitutive equations. Our results show that the Onsager’s reciprocity relations are consequences of the suggested variation principle. Furthermore, we show by the example of the thermo-diffusion such reciprocity relations for diffusion tensor, which are missing in Onsager’s theory. Our theorem applied to the non-linear constitutive equations indicates the existence of dissipation potential. We study the forms of general reciprocity with the dissipation potential. This consideration results in a weaker condition than Li-Gyarmati-Rysselberhe reciprocity has. Furthermore, in the case of electric conductivity in the magnetic field, our theorem shows the correct dependence of the Onsager’s kinetic coefficient by the axial vector of magnetic induction. We show in general that the evolution criterion of the global entropy production is a Lyapunov-function, and so the final stationer state is independent of the initial, time-independent boundary conditions.

scholarly journals The principle of minimum entropy production and snow structure

2004 ◽  
Vol 50 (170) ◽  
pp. 342-352 ◽  
Author(s):  
Perry Bartelt ◽  
Othmar Buser
Keyword(s):  
Mass Transfer ◽  
Temperature Gradient ◽  
Entropy Production ◽  
Surface Curvature ◽  
The State ◽  
Temperature Gradients ◽  
Curvature Radius ◽  
Minimum Entropy ◽  
Snow Layer ◽  
Minimum Entropy Production

AbstractAn essential problem in snow science is to predict the changing form of ice grains within a snow layer. Present theories are based on the idea that form changes are driven by mass diffusion induced by temperature gradients within the snow cover. This leads to the well-established theory of isothermal- and temperature-gradient metamorphism. Although diffusion theory treats mass transfer, it does not treat the influence of this mass transfer on the form — the curvature radius of the grains and bonds — directly. Empirical relations, based on observations, are additionally required to predict flat or rounded surfaces. In the following, we postulate that metamorphism, the change of ice surface curvature and size, is a process of thermodynamic optimization in which entropy production is minimized. That is, there exists an optimal surface curvature of the ice grains for a given thermodynamic state at which entropy production is stationary. This state is defined by differences in ice and air temperature and vapor pressure across the interfacial boundary layer. The optimal form corresponds to the state of least wasted work, the state of minimum entropy production. We show that temperature gradients produce a thermal non-equilibrium between the ice and air such that, depending on the temperature, flat surfaces are required to mimimize entropy production. When the temperatures of the ice and air are equal, larger curvature radii are found at low temperatures than at high temperatures. Thus, what is known as isothermal metamorphism corresponds to minimum entropy production at equilibrium temperatures, and so-called temperature-gradient metamorphism corresponds to minimum entropy production at none-quilibrium temperatures. The theory is in good agreement with general observations of crystal form development in dry seasonal alpine snow.

scholarly journals Seeking minimum entropy production for a tree-like flow-field in a fuel cell

2020 ◽  
Vol 22 (13) ◽  
pp. 6993-7003 ◽  
Author(s):  
Marco Sauermoser ◽  
Signe Kjelstrup ◽  
Natalya Kizilova ◽  
Bruno G. Pollet ◽  
Eirik G. Flekkøy
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Entropy Production ◽  
Minimum Entropy ◽  
Murray's Law ◽  
Field Patterns ◽  
Murray’S Law ◽  
Minimum Entropy Production

We show how we can improve bio-inspired flow field patterns for use in PEMFCs by deviating from Murray's law.

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