Electrohydrodynamically induced dielectric liquid flow through pure conduction in point/plane geometry-theory

Mildly polar liquids generally exhibit an ohmic behavior when subjected to electric fields of limited values. The resulting conduction is then associated with heterocharge layers of finite thickness in the vicinity of the electrodes. In this paper, a simple conduction model is briefly presented which is based on the processes of dissociation of a neutral electrolytic species and recombination of the generated ions. This model is then applied to parallel plane electrode geometry to describe the build-up of the heterocharge layers and to obtain an approximate solution. Then, the case of point/plane configuration is considered where the effect of Coulomb force is different in the two layers next to the electrodes. A net motion toward the point electrode is predicted to occur. Taking into account the variation law of the harmonic field along the field lines, an approximate analysis is presented and an expression for the axial component of the total force exerted on the liquid is provided.