Influence of the gravity on interface shape during crystal growth of LICAF

A Galerkin finite element method, together with the boundary conformal mapp ing technique, is used to investigate the change of melt/crystal interface under low gravity during the growth of LICAF system. Results have shown tha t strong convection can cause a deeply concave interface toward the crystal , and significantly increase radial thermal gradients near the interface. T he flow intensity and the change of the gravity have a linear relationship under low gravity ( g(0) = 10(-2)-10(-6)). At small Ma number, the maximum acceleration for keeping a planar growth interface is g(max) = 1 x 10(-3) g under our given conditions. In addition, the growth velocity may have some influence on the growth interface shape even at mu g gravity level, indica ting that the growth velocity cannot be too fast even when convection is ve ry weak.