Electro-thermo-convection in a differentially heated square cavity under arbitrary unipolar injection of ions

A numerical investigation of electro-thermo-convection in a 2-D differentially heated square cavity filled with a dielectric liquid is presented. Fully coupled governing equations of electric potential, charge transport, Navier–Stokes equations, and the energy equation are implemented in the finite-volume framework of OpenFOAM®. For this kind of electro-thermo-convection, previous studies mainly focused on the strong injection regime. This study extends the analysis to arbitrary injection strengths in weak, medium and strong regimes. Moreover, the flow configuration considered in this study investigates the simultaneous action of buoyancy and Coulomb forces acting in orthogonal direction to each other. For strong and medium injection, the flow transforms from a steady two-cell flow to a periodic two-cell flow and finally evolves into a chaotic flow with multiple cells, as the value of T is increased. In the weak injection regime, chaotic flow with multiple flow cells is observed right from the onset of instability. Heat transfer rates and the maximum velocity are directly proportional to the electric Rayleigh number T. Present study gives an insight into different flow structures and the related heat transfer phenomenon at arbitrary injection strengths.