NUMERICAL-SIMULATION ON DUMPING OF CONVECTION BY ROTATING A HORIZONTAL CYLINDER DURING CRYSTAL-GROWTH FROM VAPOR

Rotation of a horizontal cylinder is proposed as a new method to suppr ess the convective transport in the crystal growth from vapor. Numeric al calculations are carried out in order to evaluate the effect of thi s method. The reduction of Sherwood number (Sh) is confirmed and other characteristic features of this method are found as described below. The transient increases of flow velocity accompanied by the transition from the boundary-layer-driven regime (BLDR) to the core-driven regim e (CDR), and the occurrence of a counter flow near the center of the c rystal surface are found. Though the counter flow causes the nonunifor mity of Sh across the interface, the choice of optimum rotational freq uency, which enables both reducing Sh and avoiding the nonuniformity o f Sh, is presented. (C) 1998 Elsevier Science B.V. All rights reserved .