Electromagnetic enhancement of turbulent heat transfer

We performed large eddy simulations (LES) of the turbulent natural convection of an electrically conductive fluid (water with 7% Na2SO4 electrolyte solution) in a moderate (4:4:1) aspect ratio enclosure heated from below and cooled from above and subjected to external nonuniformly distributed electromagnetic fields. Different configurations with permanent magnets (located under the lower thermally active wall, B0=1 T) and different strengths of imposed dc electric currents (I=0–10 A) were compared to the case of pure thermal convection in the turbulent regime, Ra=107, Pr=7. It is demonstrated that the electromagnetic forcing of the boundary layers caused significant reorganization of flow and turbulence structures producing significant enhancement of the wall-heat transfer (up to 188% for a configuration with 35 magnets and an applied dc current of 10 A).Multi-Scale PhysicsApplied Science