Numerical investigation of the heat transfer in cylindrical annulus with a dielectric fluid under microgravity

Abstract

Three-dimensional (3D) flow driven by thermal convection in a dielectric liquid confined in the gap between two coaxial cylinders is investigated by direct numerical simulations. The inner surface is warmer than the outer one and a high frequency alternating electric tension is applied to the cylinders. The fluid is therefore subjected to a radial dielectrophoretic force which plays the role of a buoyancy force that can generate a thermal convection. We have performed 3D simulations using periodic boundary conditions. The transition from the base state to convective flow occurs via a supercritical bifurcation and leads to helicoidal stationary vortices. The behavior of the heat transfer by convective flow is investigated for different values of the radius ratio, Prandtl number, and electric Rayleigh number.