Influence of the characteristic parameters on flow patterns and heat transfer in electro-thermo-convection

Abstract

We study the electro-thermo-convective phenomena in a dielectric liquid layer of depth H placed between two electrodes and subjected to the simultaneous action of an electric field and a thermal gradient. The full set of governing equations is directly solved using a finite volume method. In this paper we first heat from the lower electrode and apply the electric potential when the thermal steady state is obtained. Only the case of strong injection of electric charges is considered. The flow pattern and Nusselt number strongly depend on the following non dimensional characteristic parameters: electrical parameter T, Rayleigh number Ra, Prandtl number Pr and mobility parameter M. The electro-convective flow structure is analysed in a rectangular cavity of length 2H, where the pure thermo-convection gives rise to two rolls whereas the pure electro-convection (with injection) gives a four roll pattern. The combined effect of both electric and thermal field on the flow patterns and on Nusselt number is analyzed for different values of Pr and M.