Derivation of a correlation formula for the effective thermal conductivity of geological porous materials by the three-phase geometric-mean model

1998 ◽  
Vol 30 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Hiroshi Kiyohashi ◽  
Mamoru Deguchi
Author(s):  
Deepak Shah ◽  
Alexey N. Volkov

A numerical method to solve thermal transport problems in powder bed systems and porous materials with finite thermal contact conductance at interfaces between individual powder particles or grains is developed based on the Smoothed Particle Hydrodynamics approach. The developed method is applied to study the effective thermal conductivity of two-dimensional random powder bed systems with binary distribution of powder particles radii. The effects of particle size distribution parameters, density parameter, and effective interface area between particles on the effective thermal conductivity are studied. It is found that at finite Biot number, which characterizes the ratio of the interfacial conductance to the conductance of the bulk powder material, the effective thermal conductivity of porous samples increases with increasing fraction of particles of larger size.


Author(s):  
Fabio Gori ◽  
Sandra Corasaniti

The aim of the present paper is to determine the effective thermal conductivity of three-phase soils, made of a quasi-spherical solid grain, and surrounded by two phase, which can be water and air or water and ice. The effective thermal conductivity is obtained theoretically by integrating the conduction equation under the thermal distribution of parallel heat fluxes in steady-state. The effective thermal conductivity is evaluated at a given degree of porosity (ratio between the void volume and the total one) and different degrees of saturation (ratio between the water volume and the void one) from dryness up to saturation. Comparisons between experimental data and theoretical predictions confirm that the present model can predict the effective thermal conductivity with a fairly good agreement without using any empirical constant.


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