Oscillatory thermocapillary convection features in a liquid bridge under normal gravity and microgravity conditions—Drop shaft experiments

Abstract

Abstract From normal gravity experiments, it is shown that the critical temperature difference (ΔTc) is very sensitive to (V/Vo). These results suggest that striation of grown crystals can be controlled by the volume of the melt. Under the μ g conditions the stable ranges disappeared in the case of short liquid bridges (L=1.6–2.5mm). In the case when L=3.3mm, it was observed that there are particular ranges of V/Vo and ΔT where the convection is steady under μ g condition but oscillatory under 1g conditions. These results suggest not only that the critical temperature difference varies with gravity level, but also that the effect of melt volume on the quality of grown crystal is strong, and that μ g conditions are more favorable than the 1g condition to grow high quality single crystals. The various temperature oscillatory features defined as 5 oscillatory features. They were shown on a ΔT-V/Vo plane diagram under 1g and μ g conditions each. In these experimental conditions, after gravity was changed from 1g to μ g conditions, only the periodic feature was exhibited in all temperature oscillatory convection.