Numerical simulation of thermo-solutal Marangoni convection in a floating half-zone with radiation effects under zero gravity

Abstract

Numerical simulations of thermo-solutal Marangoni convection in a floating half SiGe zone with radiation effects under zero gravity have been carried out. In this system, thermal and solutal Marangoni flows develop along the melt free surface either in the same direction or opposite directions depending on the directions of thermal and solutal gradients. In present model of a half SiGe zone, the ambient temperature is kept constant. Radiation due to heat loss and heat gain is considered as the dominant heat transfer mechanism from the ambience. Transition mode maps, based on concentration distribution with respect to Marangoni ratio (Rσ=MaC/MaT) and ambient temperature (Ta), have been developed to investigate the effect of radiation at unequal or equal (MaC, MaT) values. The maps reveal the main concentration structures and potential transitions at various Ta values. The opposite thermo-solutal Marangoni flows give rise to more complex structures than those of the same-direction flows. Both heat loss and heat gain may alter or destabilize the concentration distribution in the melt. However, to some extent, heat loss in the opposite-direction flow case provides a stabilizing effect on the azimuthal wave pattern at a lower or higher Rσ value.