Joule heating effects on dielectric fluids in EHD-enhanced thermoconvection within a ventilation system

This study presents numerical simulations to examine the electro-thermo-convection effects on an unsteady combined convection in a square cavity with a central square obstacle. The obstacle's walls acted as an electrical emitter, while the cavity walls served as a collector, with the remaining walls insulated. Using the finite difference method with an alternate direction implicit scheme and successive under-relaxation, we investigated the impact of key parameters such as Reynolds number (Re=100), Richardson numbers (1≤Ri≤20), Prandtl numbers (1≤Pr≤156), charge injection parameter (0.2≤C≤100), and electrical Rayleigh numbers (0≤Ra_e≤1200), including Joule heating effects. The results showed that increasing the electrical Rayleigh numbers enhanced heat transfer by 89% in pure electro-convection cases. However, when buoyancy forces and electrical effects were combined at high electrical intensities, a reduction in heat transfer efficiency was observed. These findings demonstrate a complex interaction between thermal and electrical effects, where stronger electrical forces can suppress the positive impact of buoyancy on heat transfer. Overall, the numerical results align well with previous studies, highlighting the potential for these combined effects to be applied in the development of advanced cooling technologies for electronic devices and other thermal management systems.