Flow structure and heat transfer of electro-thermo-convection in a dielectric liquid layer

Electrothermohydrodynamic flow of dielectric liquid in a square cavity driven by the simultaneous action of Coulomb and buoyancy forces is studied numerically. A high resolution upwind scheme is applied to study the flow bifurcations and heat transfer. We focus on the strong injection case with the nondimensional injection parameter C fixed at C = 10. Two Prandtl numbers Pr = 1 and Pr = 10, two Rayleigh numbers Ra = 10(5) and Ra = 10(6), as well as two mobility numbers M = 10 and M = 20 are considered to evaluate the dependence of flow structure and heat transfer on these parameters. Multistates are found to coexist in a wide range of parameter regimes. Various flow patterns such as one-cell, two-cell, four-cell, and multicell flow are observed. The electric field is found to enhance heat transfer more efficiently for large Prandtl number fluid at low mobility parameter and relatively low Rayleigh number.