Terminal velocity of single charged drops through dielectric liquid in a uniform electric field.

Abstract

Stewart and Thornton5] proposed an electrostatic liquid-liquid extractor in which a larger inter facial area of liquid drops and a higher degree of turbulence within and around the drops were produced by applying an electric field. Recently, theoretical and experimental studies have been performed for formation of single charged drops in dielectric liquids in the presence of a uniform electric field7) and for mass transfer rates between the drops and the surroundings.1'T he present study was undertaken to observe the terminal velocity of single charged drops in the electric field, which is an important factor for study of mass transfer rates in the extractor, and to provide basic information for practical design of the extractor.

The effect of electric field on mass transfer from drops dispersed in a viscous liquid

“…higher droplet velocities resulting from EHD forces of repulsion exerted on the charged drops in the direction of motion (Thornton, 1968;Bailes, 1981;Takamatsu et al, 1983;Yamaguchi et al, 1985;Vu and Carleson, 1986); enhanced circulations inside and around droplets due to the tangential component of the EHD forces exerted on the droplet surface (Morrison, 1977;Griffiths and Morrison, 1979;Chang et al, 1982;Chang and Berg, 1983); induced droplet oscillations by electric field due to the droplet deformation effect (Thornton, 1976;Wham and Byers, 1987;Scott and Byers, 1989;Basaran et al, 1989;Scott et al, 1990;Yang and Carleson, 1991); interfacial-tension-induced flow by the local variations in the effective interfacial tension due to the presence of electrical charges (Austin et al, 1971;Iyer and Sawistowski, 1974;Carleson and Berg, 1984;Berg, 1985a, 1985b;Carleson and Fuller, 1987). The basic techniques to achieve electrically enhanced liquid-liquid extraction are briefly summarized in Table 1.…”