Czochralski setup parameters

Czochralski process parameters. 

Figure 3.  Czochralski process parameters.

Crystal rotation

The frequency (Hz) of the crystal rotation is entered in Hz: for conversion from rotations per second 1 RPM = 1/60 Hz.

This parameter can be used for the automatic setting of the boundary condition for the azimuthal velocity in case of the hybrid mesh with phase transition.

If the melt convection is computed on the unstructured mesh and the enthalpy method is used, then the Dirichlet values for the azimuthal velocity at the melt-crystal interface are set also automatically each time after the nodes at the isothermal interface crystal-melt are shifted.

Crucible rotation

The frequency (Hz) of the crucible rotation, the same unit conversion as for the crystal.

This parameter can be used considering the Czochralski configuration on the hybrid mesh. Azimuthal velocities everywhere at the interface melt-crucible are set automatically.

Computing melt convection on the unstructured mesh the crucible rotation rate parameter cannot be used.

Automatic boundary setup for structured mesh

This option works in conjunction with the hybrid model of the phase transition. It activates a procedure of automatic setting of the Dirichlet boundary values for azimuthal velocity component everywhere at the outer interface of the melt along its contact with the crystal and with the crucible.

The phase transition should be defined by the structured mesh generation. The crystal and crucible rotation frequencies from this dialog window will be applied for setting of the azimuthal boundary conditions.

Translation heat flux

The additional heat flux due to the movement of the crystal is included as a quasi-steady approximation in the temperature computation.

Heat flux inside crystal: the additional heat flux due to the movement of the crystal is included as a quasi-steady approximation in the temperature computation.

Note

One should avoid this setting because this model is valid only for an infinitely long crystal, otherwise the convective heat flux due to the crystal translation will be not balanced with the radiative and conductive heat fluxes on the top of the crystal.