An Exact Solution of the Sublimation Problem in a Porous Medium

1981 ◽  
Vol 103 (1) ◽  
pp. 165-168 ◽  
Author(s):  
Sui Lin

Sublimation problem with coupled heat and mass transfer taking place in a porous halfspace is defined and exact solutions for temperature and moisture distributions as well as the position of the moving sublimation front are obtained. The condition for the limitation of the sublimation process is also determined.

2005 ◽  
Vol 21 (1) ◽  
pp. 57-62 ◽  
Author(s):  
I-C. Liu

AbstractAn analysis is performed to the study of the momentum, heat and mass transfer of a viscous fluid-saturated porous medium past an impermeable, non-isothermal stretching sheet with internal heat generation or absorption and chemical reaction. The governing partial differential equations are converted into ordinary differential equations by means of a similarity transformation. Exact solutions of velocity components together with the pressure distribution, which can not be found in the boundary layer theory, are obtained analytically; in addition, the temperature and concentration functions are given in terms of confluent hypergeometric functions. The velocity, temperature (concentration) profiles and thermal characteristics at the sheet for relevant parameters are plotted, tabulated and discussed.


2009 ◽  
Vol 36 (6) ◽  
pp. 524-537 ◽  
Author(s):  
P. A. Lakshmi Narayana ◽  
P. V. S. N. Murthy ◽  
P. V. S. S. S. R. Krishna ◽  
Adrian Postelnicu

2012 ◽  
Vol 9 (1) ◽  
pp. 91-93
Author(s):  
U.R. Ilyasov ◽  
A.V. Dolgushev

The problem of volumetric thermal action on a moist porous medium is considered. Numerical solution, the influence of fluid mobility on the dynamics of the heat and mass transfer process is analyzed. It is established that fluid mobility leads to a softer drying regime. It is shown that in low-permeability media, the fluid can be assumed to be stationary.


Author(s):  
Boris G. Aksenov ◽  
Yuri E. Karyakin ◽  
Svetlana V. Karyakina

Equations, which have nonlinear nonmonotonic dependence of one of the coefficients on an unknown function, can describe processes of heat and mass transfer. As a rule, existing approximate methods do not provide solutions with acceptable accuracy. Numerical methods do not involve obtaining an analytical expression for the unknown function and require studying the convergence of the algorithm used. The value of absolute error is uncertain. The authors propose an approximate method for solving such problems based on Westphal comparison theorems. The comparison theorems allow finding upper and lower bounds of the unknown exact solution. A special procedure developed for the stepwise improvement of these bounds provide solutions with a given accuracy. There are only a few problems for equations with nonlinear nonmonotonic coefficients for which the exact solution has been obtained. One of such problems, presented in this article, shows the efficiency of the proposed method. The results prove that the proposed method for obtaining bounds of the solution of a nonlinear nonmonotonic equation of parabolic type can be considered as a new method of the approximate analytical solution having guaranteed accuracy. In addition, the proposed here method allows calculating the maximum deviation from the unknown exact solution of the results of other approximate and numerical methods.


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