EHD convection in a dielectric liquid subjected to unipolar injection: Coaxial wire/cylinder geometry

Abstract

The injection of charge carriers into a dielectric liquid lying between a wire and a coaxial cylinder generally induces a motion of the liquid. The characteristics of the convection and its effect on the passage of electrical current are examined with reference to the similar electro-convection which exists in a planar layer of liquid. After recalling the main results obtained in the latter geometry for both weak and space charge limited injections, a rough analysis is developed in the case of strong injection in an annulus. It gives some expressions for the typical convective velocities. The experimental determination of the variation laws of the current and of the typical velocity apparently reveals the occurrence of two conduction regimes. The analogies and differences with the characteristics of the regimes of convection in a planar layer are indicated and discussed.