Marangoni Convection in Liquid Bridges due to a Heater/Cooler Ring

Abstract

Liquid-liquid systems in contact with solids often give rise to the formation of liquid bridges. Such geometries generated by fluids are exploited in a variety of scenarios ranging from specialized rheometers to silicon crystal production. The presence of immiscible fluid-fluid interfaces and thermal, solutal or electric field gradients cause such systems to exhibit Marangoni effects. In the present study, we have chosen a capillary bridge of water bounded by two solid insulated discs surrounded by silicone oil. This liquid bridge has been subjected to a heater or cooler ring around it. We study the fluid dynamics and heat transfer due to the ring for different heater/cooler locations. We observe drastic differences between heater and cooler configurations in terms of the maximum interfacial velocities, net heat transferred to the bridge and location of the stagnation points. Flow and bridge shape is seen to be more stable in the cooler ring cases. Anomalous results for heat transfer rate, interface deformation and circulation patterns are obtained in the heater configuration for larger height to radius ratios. Moreover, when the heater/cooler ring is placed close to the solid discs, anomalous dynamics is observed.