THERMAL BUOYANCY AND MARANGONI CONVECTION IN A 2 FLUID LAYERED SYSTEM

Thermal buoyancy and surface tension driven convection is numerically investigated in a system with two immiscible fluids. The geometry inve stigated has an open cavity configuration with the lighter fluid situa ted on top of the heavier fluid, forming a stable layered system. The upper fluid meniscus and the interface are assumed to be flat and unde formable in the calculations. The governing equations and boundary/int erface conditions are solved by a control volume-based finite differen ce scheme for two pairs of immiscible fluids; the water-hexadecane sys tem and a so-called generic system. The steady-state calculations pred ict dramatically different flows when interfacial tension effects are included or excluded from the system model. These differences are part icularly appreciable in surface tension-dominated flows, that are typi cal of microgravity situations. Complex flow patterns, with induced se condary flows, are noticed in both the fluids. In general, the overall system heat transfer is found to increase with increases in the therm al buoyancy and surface tension effects, but the behavior of the syste m flow and thermal fields is not easy to characterize when different c ombinations of these forces are considered.