Statistical Mechanics of Irreversible Processes and the Principle of Minimum Entropy Production

1965 ◽  
Vol 139 (4A) ◽  
pp. A1156-A1158 ◽  
Author(s):  
J. D. Currin
Keyword(s):  
Statistical Mechanics ◽  
Entropy Production ◽  
Irreversible Processes ◽  
Minimum Entropy ◽  
Minimum Entropy Production

CONDITIONS OF MINIMAL LOSS OF EXERGY IN NON-EQUILIBRIUM PROCESSES OF ACTUATING MEDIUMS HEAT EXCHANGE

2017 ◽  
pp. 30-34
Author(s):  
V.P. Bondar
Keyword(s):  
Heat Exchange ◽  
Entropy Production ◽  
Temperature Difference ◽  
Irreversible Processes ◽  
Minimum Entropy ◽  
Equilibrium Processes ◽  
Minimum Entropy Production ◽  
Equilibrium Process ◽  
Internal Irreversibility ◽  
Non Equilibrium

Heat exchange of actuating mediums in heat-exchanging apparatuses runs non-equilibrium (irreversibly), causing loss of operational part of heat. Two types of non-equilibrium process are distinguished: external and internal. External irreversibility is function of average temperature difference (irreversibility degree) and relation of incomplete recuperation on heat exchange boards of actuating mediums. Nature of internal non-equilibrium processes is related to friction work of actuating mediums that are practically impossible to be taken into account and described analytically. In this article, in order to define conditions of change of current temperature difference by exponential law, external and internal irreversibility are reviewed both mutual and separately. Change of current temperature difference by exponent is one of conditions of minimal numeric value of entropy production of system in non-equilibrium processes of actuating mediums heat exchange existence. Analysis, performed in article, along with example, are evidence that at all types of irreversible processes of actuating mediums heat-exchange, exist conditions of gaining the numeric value of minimum entropy production and exergy losses. Bibl. 8, Fig. 1.

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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