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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Influence of crystal rotation on the convective heat transfer For Y3Al5O12 in Czochralski crystal growth

Get access (open in a dialog) DOI: 10.1615/IHTC12.3800
6 pages

要約

The steady state Navier−Stokes equation with Boussinesq approximation,the continuity equation and energy equation in cylindrical coordinates (Wheeler,1990) were solved for a Czochralski crucible containing molten YAG ( Y3Al5O12). In these calculations, a new set of boundary conditions with respect to previous works was considered and solutions were computed by finite difference / iteration method. For solutions, the Reynolds number Re characterized the forced convection caused by crystal rotation rate ( ωs ),and the Grashof number Gr represented the intensity of buoyant driving forces arising from temperature difference between the crucible side wall and crystal-melt interface ( Tmax). The mixed flow in the melt can be nearly classified into three types with respect to different values of Gr/Re2 . For low Gr/Re2 ( < 0.5 ) the forced convection is only predominate in the melt, while for high Gr/Re2 ( >5 ) the free convection is dominant. For middle values of Gr/Re2 ( ~1 ),the free and forced convection both are considerable and present in the molten material. Also, there is a surface pattern (a circular dark line) on the melt free surface. The temperature field considerably depends on the both crystal rotation rate and thermal boundary conditions.