Thermocapillary convection in liquid-in-liquid capillary bridges due to a heating/cooling ring

Abstract

A liquid bridge connecting two solid disks is surrounded by a heating/cooling ring in the presence of another immiscible liquid. The thermocapillary convection and the interface deformation thus generated in a gravitational environment are studied for a range of bridge aspect ratios and ring temperatures using 2D axisymmetric simulations. A stark difference between the heater and cooler cases is observed in their flow and heat transfer patterns. Interfacial velocity and bridge deformation are seen to be more stable when a cooling ring surrounds the liquid bridge. Fluid trajectories inside the bridge show longer paths as the temperature difference between the cooler/heater and the surroundings is raised. Moreover, a cooler lessens the deformation, whereas a heater enhances the deformation of the phase interface. Anomalous results for a heat transfer rate, interface deformation, and circulation patterns are obtained in the heater configuration for larger height to radius ratios.