Field-Enhanced Motion of Impurity Particles in Fluid Dielectrics under Linear Conditions

Abstract

It has been pointed out by several authors that the influence of impurity particles on dielectric phenomena in non-solid dielectrics can be significant in some cases, especially for technical liquids. In order to get information on such impurity influence, a computer-aided study of the motion of a charged spherical particle under general transient conditions, and with unrestricted conductivity and permittivity of both the medium and the particle has been carried out. To verify the model consistency, a set of tests in n-hexane with sphere-plane electrode geometry have been carried out using different experimental techniques, including high-speed-photography, and satisfactory agreement has been observed. On this basis, a model of the low-field conduction process by impurity particles has been developed assuming negligeable interactions between particles. A computer-aided procedure for the evaluation of impurity convection currents under different conditions has been implemented. The results obtained are compared with tests carried out on n-hexane with controlled pollution. Finally, a detailed discussion of the results obtained is given.