Water drop deformation in silicone oil under high ac electric fields

Abstract

Consulta en la Biblioteca ETSI Industriales (8612)

[EN] Deformation and break-up of liquid drops suspended in another immiscible fluid under the action of an electric field are examined in this research. Usually a drop suspended in an immiscible viscous liquid under the influence of an externally applied electric field, may experience complex behaviours (deformation, motion, electrorotation, burst¿), depending on the electric field strengths and the fluid properties (viscosity, surface tension, electric conductivity, permittivity and dielectric constant). Depending on the fluid properties drop, it either deforms into prolate or oblate and it bursts if applied electric field is greater than critical field. Prolate deformation occurs in the direction of the electrical field and oblate one in perpendicular direction. The presence of insoluble non-ionic surfactant on drop liquid interface reduces the interfacial tension and thereby alters the drop motion. In general presence of surfactant affects the deformation as well as the mode of break-up. Depending on the surfactant concentration, two types of break-up mode occur, known as bulbous end formation and tip-streaming. Drop deformation in high frequency AC field is studied, frequency ranges from 1 Hz to 1000 Hz. Frequency dependency of drop deformation and exposure time effect near critical field are also after exposed. A large variety of applications of this phenomenon can be taken into consideration such as the production of water oil emulsions like mayonnaise or butter but also different Chemical Engineering mixing processes. In summary, the aim of this work is to lay first stone in the research of water drop deformation under high electric field to understand several mechanisms that can lead to industrial applications.