Homogenized models of conduction-advection-radiation heat transfer in porous media
Abstract
Upscaled models are derived from the periodic homogenization technique for conduction-convectionradiation problem in porous media for the case of an opaque solid and transparent uid. Thermal radiation at the pore-scale level is rst described through a dierential view factor between elementary surfaces. Such heat transfer mode is coupled with the conduction-convection mechanisms by a radiative ux in the uid phase and a jump of conductive uxes at the solid/uid interface. In the framework of the periodic homogenization procedure, a macroscopic model is built with upscaled eective coecients. Both cases of closed and open pores are studied. In the second case the radiative transfer cannot be restricted to the central unit cell. The radiation at the macroscale only aects the eective conductivity. The validity of the approach is illustrated by some simple examples. The main objective of this work is to establish the macroscopic equation form of the conduction-convection-radiation problem and to understand how the radiation aects the macroscopic behavior.
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