Flow transition and heat transfer enhancement in electrothermal convection of dielectric liquids in a finned cavity

Electrothermal convection of dielectric liquids in a finned cavity has been investigated numerically. The coupling governing equations of the Navier–Stokes equations, the electric potential equation, the charge conservation equation and the energy equation are solved in the finite volume method framework of OpenFOAM®. The effect of electric field on flow and heat transfer enhancement property has been systematically discussed. With the increase in the electric Rayleigh number T, there is a flow transition of electrothermal convection from the unsteady to steady and then back to unsteady state. The flow pattern of electrothermal convection is established. Moreover, the heat transfer performance of the finned cavity increases with the increase in T, and the enhancement effect of electric field is better for a low Rayleigh number Ra. As T increases from 0 to 2000 at Ra = 103, the average Nusselt number Nuave increases by 11.77 times. It is advantageous to select dielectric fluids with the properties of smaller dimensionless mobility M and larger Prandtl number Pr for electric field enhancing heat transfer. This study aims to provide a reference for the design of the finned heat exchanger coupled with electric field.