3-DIMENSIONAL FLOW TRANSPORT MODES IN DIRECTIONAL SOLIDIFICATION DURING SPACE PROCESSING

A numerical model for the proposed GTE GaAs space experiment is presented. The model includes the actual ampule design and the experimentally obtained furnace thermal profiles. It is demonstrated that the commonly presumed axisymmetric flows in numerical studies are physically reasonable only when the local gravitational acceleration vector is parallel to the ampule's axis. Other gravitational orientations result in nontrivial three-dimensional flows that must be resolved using full three-dimensional models. Implications of the resulting flow and thermal fields on the growing crystal at conditions available during space processing are also discussed.