Lattice Boltzmann simulation of electro-hydro-dynamic (EHD) natural convection heat transfer in horizontal cylindrical annuli

The natural convection heat transfer in a dielectric liquid confined in horizontal cylindrical annuli and enhanced by imposing a direct current electric field is numerically investigated using a unified lattice Boltzmann method. This augmentation of heat transfer is attributed to the flow motion induced by the Coulomb force due to the electric field exerting on free charges injected from the inner cylinder. Both concentric and eccentric configurations are considered. It is found that there exists a threshold of the electric driving parameter T, above which the heat transfer enhancement due to the electric effect becomes significant for concentric cases. For eccentric configuration, this change becomes relatively gentle. In addition, the influence of the eccentricity on heat transfer enhancement is also studied.