General process parameters

Under specific circumstances modifying the general process parameters is necessary, e.g. for computing latent heat of materials or for experiments in space.

Growth rate

You need to specify the estimated growth rate of the crystal for pseudo-stationary computations. The growth rate has to be specified in m/s. For the pure unstructured mesh the growth rate has to be positive, if the interface between the solid and the liquid phase is moving upwards in positive z-direction as in VGF furnaces. The growth rate has to be negative, if the interface is moving down in negative z-direction as in Czochralski furnaces.

For the hybrid mesh the sign of the growth rate doesn't depend on the crystal growth arrangement. The positive sign affects always the release of crystallization latent heat and the negative sign corresponds to to the heat consumption by the "negative growth" or crystal melting. The same applies if doing tracking on the unstructured mesh, but not using the enthaly method.

Note

In time-dependent computation the growth rate must be set to 0.

Gas pressure

The gas pressure (N/s²) has to be specified for computing convection, if the ideal gas model has been chosen.

Gravity

Default is the gravity of the earth (9.81 m/s²). This value is used to compute buoyancy forces for convection.

Latent heat

The latent heat in J/m³ has to be specified for computing the phase transition crystal-melt, if it is modeled by means of the hybrid mesh.

In this case the phase boundary separates two regions filled with different single phase materials, the crystal region with the solid phase and the melt region with the liquid phase. Therefore the phase transition heat isn't refering anymore to a material as it was the case for the enthalpy method and pure unstructured mesh. In the enthalpy method the latent heat is entered as a material property in J/kg. The same value but multiplied with the density of the crystal is expressed in J/m³ and should be prescribed as a process parameter for the hybrid mesh model.

The dialog field for the latent heat in the process parameters window remains hidden if no phase transition on the hybrid mesh is created. Otherwise it gets visible as shown in the figure below.

General process parameters. The latent heat dialog field is visible while the phase transition on the hybrid mesh is considered. 

Figure 2.  General process parameters. The latent heat dialog field is visible while the phase transition on the hybrid mesh is considered.