Investigations on Electroconvection Under AC Electric Field in Dielectric Fluids

Abstract

Electro hydrodynamics (EHD) finds wide applications in many processing industries and rising technologies. For better heat transfer, electrical force plays an important role in driving the motion of a dielectric fluid with a low electrical conductivity. Transformer oil (and most other organic substances) and distilled water are examples of such fluids. Fluid motion driven by thermal gradients in the presence of gravity, known as thermos gravitational convection, is a common and important phenomenon in nature and also in many engineering applications. Over the years, quest to understand convective flows has influenced numerous experimental and theoretical research. In spatially extended systems, convection normally occurs whilst a sufficiently steep temperature gradient is applied across a fluid layer. The study of fluid flow and heat transfer in fluid-saturated porous media has also attracted researchers due to its natural occurrence and relevance in different fields of interest, from engineering to geophysics and space applications. The electro convection phenomenon is among the pre-breakdown phenomena that influences the dielectric strength of insulating oils. In transformer mineral oils, electro convection results in catastrophic failure of transformers. It is important to analyze the effect of parameters consisting of buoyancy, surface tension and viscosity. The work also provides an insight to the manufactures about the range of the parameters to be chosen for better heat transfer to take place. newline