A lattice Boltzmann analysis of the electro-thermo convection and heat transfer enhancement in a cold square enclosure with two heated cylindrical electrodes

In this paper, the electro-thermo convection (ETC) of a perfectly insulted liquid induced by two energized and heated circular cylinders in a cold square cavity is numerically discussed. The abundant flow motion phenomenen are comprehensive results of the buoyancy force and Coulomb force. A newly developed unified lattice Boltzmann (LB) model for flow field, electric potential, charge density and temperature field is applied to direct numerical simulations. Influences of Rayleigh number Ra, electric Rayleigh number Ra-E on heat transfer enhancement are studied under strong charge rejection regime. Based on the numerical results, it is found that the efficiency of heat transfer decreases with the rise of Ra, and the contributions made by external electric field for heat transfer enhancement can be ignored when Ra is sufficiently large. While the heat transfer capacity always enhances as the increase of Ra-E, especially when parameter Ra-E exceeds a critical threshold. Additionally, the effects of geometric parameter delta on heat transfer coefficient are also analyzed.