Numerical Simulation of Hydrothermal Autoclave for Single-Crystal Growth Process

Abstract

Numerical simulation of the hydrothermal process for growing two-inch bulk single crystals of ZnO has been done. The autoclave is assumed to be axisymmetric. The heat transfer by natural convection is discussed for flat and funnel-shaped baffles. The funnel-shaped baffle leads to a significant increase in the flow rate between the raw material zone and the crystal growth zone. However, the temperature difference between the two zones does not become very small. Therefore, the funnel-shaped baffle is effective in the hydrothermal crystal growth process from the viewpoint of transport phenomena. The calculations show that the optimum baffle angle about 20 degrees. Similar results are obtained when the raw material is considered as a porous medium.