A special insulated crucible susceptor in a directional solidification (DS) furnace was designed to preserve seed crystals during the melting process and to optimize the thermal field in the hot-zone during the seeded solidification process. A global numerical model was established to investigate the effects of the transformation, and the model has been validated by comparing the simulation to the experimental measurements. The results of the simulation indicated that the crucible susceptor described here can Facilitate the preservation of seed crystals very effectively and that it does so by constructing a suitable temperature gradient and a flat seed-melt (s-m) interface. The casting experiments confirmed that the variations in the height of the preserved seed crystals had changed from 10 mm in the original system to 2 mm in the new susceptor system. (C) 2013 Elsevier B.V. All rights reserved.