Journal of Crystal Growth, Vol.300, No.2, 486-496, 2007
Numerical study to investigate the effect of partition block and ambient air temperature on interfacial heat transfer in liquid bridges of high Prandtl number fluid
Surface heat transfer at the liquid-air interface in liquid bridges of high Prandtl number fluid is known to affect the transitional characteristics appreciably. The heat transfer characteristics under microgravity conditions become much different from those of normal gravity mainly due to the absence of natural convection. The present study deals with numerical computations of flow and heat transfer characteristics in the liquid and surrounding air and also at the liquid-air interface of thermocapillary flow in liquid bridges of high Prandtl number fluid. The governing equations are solved in the coupled domain of the liquid bridge and the surrounding air with the help of available commercial CFD software. The results obtained for a range of Marangoni numbers indicate that by placing a partition block in the air region under normal gravity conditions, the surface heat transfer characteristics of microgravity conditions could be effectively mimicked. The effect of ambient temperature on the surface heat transfer has also been investigated and it has been found that the behavior of heat transfer at the interface changes from heat loss to heat gain when the ambient temperature is increased. Moreover, the presence of partition block under normal gravity suppresses surface heat loss as well as surface heat gain similar to microgravity conditions. Streamlines and temperature contours have been presented for various conditions in order to clarify the underlying physics more meaningfully. The computed profiles for velocity and temperature at the liquid-air interface have been validated against established experimental results. (c) 2007 Elsevier B.V. All rights reserved.