Abstract
The flow and heat transfer characteristics at the liquid-air interface of thermocapillary flow in liquid bridges of high Prandtl number fluids are investigated numerically. The conservation equations of mass, momentum and energy are solved in the coupled domain of the liquid bridge and the surrounding air with the help of available commercial CFD software. The thermocapillary effect has been incorporated as a body-force term in a very thin layer adjacent to the surface. All the computations are performed under steady state conditions. The upper and lower disk temperatures are varied in such a way so as to keep the mean temperature of the liquid to be same in all cases so that the assumption of constant property values for the liquid holds accurately. The computations are performed over a range of Marangoni numbers (Ma) for fixed ambient temperature conditions but most of the results presented here correspond to Ma= 13200. It has been shown with help of Biot number variation at the interface that the effect of microgravity on the behavior of surface heat loss can be closely mimicked by using a partition boundary (PB) in the air region. The presence of PB and microgravity modify the flow and temperature fields significantly as shown in clear and distinguishable plots for streamlines and temperature contours. The computed velocity and temperature profiles at the interface are validated against well established experimental results.
