Memory behaviors of entropy production rates in heat conduction

2018 ◽  
Vol 492 ◽  
pp. 105-112 ◽  
Author(s):  
Shu-Nan Li ◽  
Bing-Yang Cao
2019 ◽  
Vol 44 (3) ◽  
pp. 217-233 ◽  
Author(s):  
Miroslav Grmela ◽  
Michal Pavelka ◽  
Václav Klika ◽  
Bing-Yang Cao ◽  
Nie Bendian

Abstract Heat conduction is investigated on three levels: equilibrium, Fourier, and Cattaneo. The Fourier level is either the point of departure for investigating the approach to equilibrium or the final stage in the investigation of the approach from the Cattaneo level. Both investigations bring to the Fourier level an entropy and a thermodynamics. In the absence of external and internal influences preventing the approach to equilibrium the entropy that arises in the latter investigation is the production of the classical entropy that arises in the former investigation. If the approach to equilibrium is prevented, then the entropy that arises in the investigation of the approach from the Cattaneo level to the Fourier level still brings to the Fourier level the entropy and the thermodynamics even if the classical entropy and the classical thermodynamics are absent. We also note that vanishing total entropy production as a characterization of equilibrium state is insufficient.


Entropy ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1117 ◽  
Author(s):  
Robin Masser ◽  
Karl Heinz Hoffmann

Endoreversible thermodynamics is a finite time thermodynamics ansatz based on the assumption that reversible or equilibrated subsystems of a system interact via reversible or irreversible energy transfers. This gives a framework where irreversibilities and thus entropy production only occur in interactions, while subsystems (engines, for instance) act as reversible. In order to give an opportunity to incorporate dissipative engines with given efficiencies into an endoreversible model, we build a new dissipative engine setup. To do this, in the first step, we introduce a more general interaction type where energy loss not only results from different intensive quantities between the connected subsystems, which has been the standard in endoreversible thermodynamics up to now, but is also caused by an actual loss of the extensive quantity that is transferred via this interaction. On the one hand, this allows the modeling of leakages and friction losses, for instance, which can be represented as leaky particle or torque transfers. On the other hand, we can use it to build an endoreversible engine setup that is suitable to model engines with given efficiencies or efficiency maps and, among other things, gives an expression for their entropy production rates. By way of example, the modeling of an AC motor and its loss fluxes and entropy production rates are shown.


Author(s):  
S. Kabelac ◽  
M. Siemer

The fuel cell, which is a highly promising candidate for high efficiency energy conversion, is not reaching expected conversion efficiencies of η > 0,5 yet. Parallel to standard explanations of loss mechanisms by means of overvoltages, a thermodynamic view of addressing irreversibilities by calculating local entropy production rates is helpful. Entropy production rates are calculated by multiplying local transport fluxes with appropriate driving forces, i.e., gradients of temperature, chemical potentials and electric potentials. These gradients have to be calculated by solving the set of constitutive balance equations. Before this tedious task is done, simplified model equations have to be used. The reversible fuel cell is the starting point of analysis. Results for a one-dimensional PEMFC are shown.


1995 ◽  
Vol 52 (1) ◽  
pp. 623-626 ◽  
Author(s):  
Ferenc Márkus ◽  
Katalin Gambár

2017 ◽  
Vol 21 (suppl. 1) ◽  
pp. 97-104
Author(s):  
Ali Brohi ◽  
Haochun Zhang ◽  
Kossi Min-Dianey ◽  
Muhammad Rafique ◽  
Muhammad Hassan ◽  
...  

The entropy production in 2-D heat transfer system has been analyzed systematically by using the finite volume method, to develop new criteria for the numerical simulation in case of multidimensional systems, with the aid of the CFD codes. The steady-state heat conduction problem has been investigated for entropy production, and the entropy production profile has been calculated based upon the current approach. From results for 2-D heat conduction, it can be found that the stability of entropy production profile exhibits a better agreement with the exact solution accordingly, and the current approach is effective for measuring the accuracy and stability of numerical simulations for heat transfer problems.


Entropy ◽  
2016 ◽  
Vol 18 (3) ◽  
pp. 87 ◽  
Author(s):  
Federico Zullo

2019 ◽  
Vol 99 (1) ◽  
Author(s):  
Philipp Strasberg ◽  
Massimiliano Esposito

2021 ◽  
Vol 103 (1) ◽  
Author(s):  
Marcus V. S. Bonança ◽  
Pierre Nazé ◽  
Sebastian Deffner

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