Effect of particle size distribution on the effective dielectric permittivity of saturated granular media

Abstract

Abstract. The effective permittivity of an unconsolidated porous material is shown to be not only a function of the permittivity of the individual components but also of the distribution of particle sizes present. Increasing width of particle size distribution for glass spheres and sieved quartz sand is demonstrated to reduce the effective permittivity of a mixture compared to the effective permittivity of the corresponding monosize material. The results are shown to lie between predictions made using the Maxwell-Garnett [1904] formula for monosize spheres and a self-similar model [Sen et al., 1981] and can be predicted by a multiple Maxwell-Garnett-based mixing model. The results demonstrate that the degree of sorting of a material will directly influence the effective permittivity of the mixture. This is beyond the effect of the change in permittivity caused by the significant change in porosity resulting from the mixing of different particle sizes.

The impact of moisture absorption on the electrical characteristics of organic dielectric materials

“…Different techniques have been used to model the electrical parameters of a composite material, for example, the Maxwell-Garnett and the Bruggeman mixing formulas [6,7].…”

A pore-size scale model for the dielectric properties of water-saturated clean rocks and soils

“…Although the existence of implicit size-scale relationships imposed by DEMA and other effective medium theories has been recognized in various studies ͑e.g., Norris et al, 1985b;Robinson and Friedman, 2001͒, the implications are usually unappreciated in the analysis and modeling of the physical properties of porous rocks and soils. Previous DEMA modeling of electrical properties has commonly characterized porous rocks and soils as a background matrix corresponding to the pore space and embedded inclusions representing solid grains.…”

The dielectric permittivity of carbonate formations from the unified microstructure model

“…The influence of the medium structure: particle shape and size distribution on the dielectric permittivity was studied in the works of Friedman and Robinson (Friedman, 1998;Friedman and Robinson, 2002;Jones and Friedman, 2000;Robinson and Friedman, 2001;Robinson et al, 2005).…”