Extended irreversible thermodynamics as a framework for transport phenomena in porous media

1992 ◽  
Vol 9 (3) ◽  
pp. 207-221 ◽  
Author(s):  
J. A. Del Río P. ◽  
M. López De Haro
Keyword(s):  
Porous Media ◽  
Transport Phenomena ◽  
Irreversible Thermodynamics ◽  
Extended Irreversible Thermodynamics

An Extended Thermodynamic Approach to Transport Phenomena in Porous Media

1990 ◽  
Vol 195 ◽  
Author(s):  
J. A. del Rio ◽  
M. López de Haro
Keyword(s):  
Porous Media ◽  
Constitutive Equations ◽  
Evolution Equations ◽  
Transport Phenomena ◽  
Irreversible Thermodynamics ◽  
Extended Irreversible Thermodynamics ◽  
Independent Variables ◽  
Extended Thermodynamic ◽  
Momentum Fluxes ◽  
Linear Irreversible Thermodynamics

ABSTRACTA formalism of extended irreversible thermodynamics (EIT) is used to study the physical aspects of heat, momentum and mass transport through porous media.The thermodynamic space is enlarged with respect to that of classical linear irreversible thermodynamics (LIT) to include the mass, heat and momentum fluxes as independent variables. The time evolution equations for such variables are derived self-consistently and reduce to the usual constitutive equations of LIT when the appropriate limits are taken. Equations that involve effects characterized by terms of second order in the gradients of conserved variables (such as the Darcy-Brinkman law) may also be derived within the same formalism. Finally, EIT provides the natural framework beyond LIT to introduce non-isothermal effects in the study of transport phenomena in porous media.

RADIATING COLLAPSE WITH VANISHING WEYL STRESSES

2005 ◽  
Vol 14 (03n04) ◽  
pp. 667-676 ◽  
Author(s):  
S. D. MAHARAJ ◽  
M. GOVENDER
Keyword(s):  
Irreversible Thermodynamics ◽  
Temperature Profiles ◽  
Junction Conditions ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Extended Irreversible Thermodynamics ◽  
Recent Approach ◽  
Dust Solution ◽  
Limiting Case

In a recent approach in modeling a radiating relativistic star undergoing gravitational collapse the role of the Weyl stresses was emphasized. It is possible to generate a model which is physically reasonable by approximately solving the junction conditions at the boundary of the star. In this paper we demonstrate that it is possible to solve the Einstein field equations and the junction conditions exactly. This exact solution contains the Friedmann dust solution as a limiting case. We briefly consider the radiative transfer within the framework of extended irreversible thermodynamics and show that relaxational effects significantly alter the temperature profiles.

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