EMPIRICAL AND THEORETICAL APPROACHES TO THE CONSTRUCTION OF DEPENDENCIES FOR CALCULATING THE DIFFUSION RESISTANCE COEFFICIENT OF POROUS MATERIALS
DOI:
https://doi.org/10.36773/1818-1112-2026-139-1-79-87Keywords:
capillary-porous material, diffusion resistance coefficient, approximation of experimental data, conductivity theoryAbstract
Using a geometrical model of a porous material, it has been shown that the diffusion resistance coefficient μ of this model depends only on the volume concentration of the conductor of the diffusing particles and its geometry. The reasons are noted for which the existing methods of measuring the coefficient μ may yield a systematic error. Based on data from four samples in which the coefficient μ was measured by the electrical conductivity method, the features of constructing empirical and semi-empirical formulas for calculating the coefficient μ as a function of the measured porosity are considered. The advantages of semi-empirical formulas, which take into account the physical nature of the phenomenon, over empirical ones are shown. However, semi-empirical formulas (as well as empirical ones) based on different samples give significantly different results for the same porosity values. The shortcomings of the empirical approach to constructing computational formulas were overcome by using a theoretical approach implemented by means of the methods of the theory of generalized conductivity in combination with geometric modeling of the material structure. In this case, the structure of the material was considered as an isotropic binary system consisting of a dielectric (solid skeleton) and a conductor of diffusing particles. An estimate is given of the systematic error in measuring the coefficient μ when using the electrical conductivity method.
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