화학공학소재연구정보센터
Journal of Crystal Growth, Vol.266, No.1-3, 182-189, 2004
Development of model-based control for Bridgman crystal growth
We study the feasibility of using crucible rotation with feedback control to suppress oscillatory flows in two prototypical vertical Bridgman crystal growth systems-a stabilizing configuration driven by a time-oscillatory furnace disturbance and a thermally destabilized configuration, which exhibits inherent time-varying flows. Proportional controllers are applied to the two systems, with volume-averaged flow speed chosen as the single controlled output and crucible rotation chosen as the manipulated input. Proportional control is able to significantly suppress oscillations in the stabilizing configuration. For the destabilized case, control is effective for small-amplitude flows but is generally ineffective, due to the exacerbating effect of crucible rotation on the time-dependent flows exhibited by this system. (C) 2004 Elsevier B.V. All rights reserved.