Dielectric Properties of Emulsions and Suspensions: Mixture Equations and Measurement Comparisons

Abstract

Dielectric properties of water-in-oil emulsions, oil in water emulsions and limestone-in-water suspensions have been measured at 2.45 GHz by an open-ended coaxial-line probe. The results were compared to various equations for the dielectric properties of mixtures. The equation by Fricke and Mudgett describes best the behavior of oil-in-water emulsions and limestone in water suspensions. For water-in-oil emulsions the equation by Lichtenecker and Rother gives the best results.

Microwave material processing—a review

“…117 A detailed experimental study on microwave heating of oil-water emulsion systems was carried out for various oil-water fractions with fixed beaker radii in a microwave oven, and it was found that resonance (maxima in average power) occurs only for fixed sample dimensions. 118 Later, Erle et al 119 studied dielectric properties of oil-inwater (o/w) and water-in-oil (w/o) emulsions at a frequency of 2.45 GHz and they proposed correlations for the effective dielectric properties of oil-water emulsions which showed well agreement with experimental results. Morozov and Morozov 120 carried out mathematical modeling on microwave heating of oil water emulsion and they found that the temperature in the center of a oil drop might exceed temperature of the surrounding medium.…”

Role of resonances on microwave heating of oil–water emulsions

“…Erle et al (2000) measured dielectric properties for various emulsions and they found that the effective dielectric properties for an oil-water emulsion are dependent on the nature of the continuous medium. Their experiments were carried out with mean droplet diameters varying between 5 and 15 m, where droplet diameters were measured in a laser diffraction system.…”

“…An analytical solution has been developed to study the influence of traveling waves on MW power distributions for a multicomponent system. The power absorption in the emulsion system depends largely on whether the continuous phase is oil or water and we modeled the effective dielectric response in oil-water emulsions, based on a recent study (Erle et al, 2000) that illustrates that dielectric response in o/w systems is quite different from that in w/o systems for similar oil-water ratios. Although the size of dispersed phases, oil or water, critically alters the internal reflections within an emulsion sample, we restrict our current studies with the droplet sizes of dispersed phases between 5 and 15 m as the deemulsification, particularly for w/o sample decreases with the smaller sizes of droplets (see Erle et al, 2000).…”

Permittivity Measurements of Biological Samples by an Open-Ended Coaxial Line

“…Examples of materials characterized using the open-ended coaxial probe include, but are not limited to: biological tissues [1], tumors [2], binary mixtures of liquids [3], particle suspensions and emulsions [4], food [5], vegetation [6], and soil [7]. The advantages of the openended coaxial probe over other techniques are that it is a broadband measurement (10 5 -10 10 Hz), requires no sample preparation, and is suitable for liquid and semisolid samples [8].…”