Electrohydrodynamic mixed convection of dielectric organic liquids in horizontal annulus flow

Electrohydrodynamic (EHD) mixed convection of dielectric organic liquids in horizontal annulus flow has been experimentally and theoretically investigated. The mean heat transfer coefficient is characterized by three dimensionless parameters: the Reynolds number, the dielectric EHD number, and the conductive EHD number. The total current voltage characteristics are significantly influenced by forced convection and decrease with increasing Reynolds number. The mean Nusselt number increases monotonically with the Reynolds number for a zero applied field and nonmonotonically depends on the Reynolds number at a fixed applied voltage. The dielectric EHD number is derived from the temperature dependence of the dielectric constant component in EHD forces, while the conductive EHD number is derived from the conduction current component in EHD forces. The mean Nusselt number increases with increasing dielectric and conductive EHD numbers.