Three-dimensional time dependent modelling of radial segregation due to weak convection.

Authors: Do-Quang, M., Amberg, G.A., Carlberg, T.
Document Type: Article
Pubstate: Published
Journal: J. Crystal Growth
Volume: 269   454
Year: 2004


A comprehensive three-dimensional, time-dependent model of heat, momentum and solute transfer during solidification is carried out to illustrate the influence of weak convection, caused by surface tension forces, on radial dopant segregation occurring in crystal growth under micro-gravity conditions. 3D adaptive finite element method is used in order to simulate the motion and deformation of the solidification interface. The geometry studied is a Bridgman configuration with a partly coated surface. The small slots in the coating gives a free surface in a controlled way, and is varied in order to alter the Marangoni flow. In this study, A comparison is made between the numerical results and the experimental results. A good agreement has been observed for the effective distribution coefficient $k_$ and for the radial segregation $\Delta c`$. The radial dopant segregation is affected by weak convection.