Numerical investigation of convective heat transfer of a droplet in a continuous medium under a time periodic electric field

The enhancement of heat transfer in a droplet due to electric-field-induced internal circulation, particularly under low Péclet number conditions relevant to droplet-based systems, has been investigated numerically. The convective heat transfer process is analyzed in the present study, assuming constant thermal and electrical properties. A numerical simulation performed to model heat transfer under three types of electric fields: uniform direct current, alternating current, and a superposed electric field consisting alternating and constant electric fields. The interfacial Nusselt number is evaluated to compare heat transfer behavior in time-periodic and constant electric fields. The results indicate the dominance of convection over conduction depending on the frequency of the applied field and the viscosity ratio between the droplet and the surrounding medium. At lower frequencies (0.1π to π rad/s) and higher viscosity ratios (1 to 100), the Nusselt number in the time-periodic field exceeds that in the constant electric field case. Furthermore, the oscillatory behavior of droplet deformation and fluid flow velocity in response to the time periodic electric field significantly influences the convective heat transfer to the droplet.