EHD CONVECTION IN A DIELECTRIC LIQUID SUBJECTED TO UNIPOLAR INJECTION- COAXIAL WIRE CYLINDER GEOMETRY

The injection of charge carriers into a dielectric liquid lying betwee n a wire and a coaxial cylinder generally induces a motion of the liqu id. The characteristics of the convection and its effect on the passag e of electrical current are examined with reference to the similar ele ctroconvection which exists in a planar layer of liquid. After recalli ng 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 t he variation laws of the current and of the typical velocity apparentl y 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.