Preparation of the furnace model

How precise do I have to make the CAD drawing?

The CAD drawing should contain all elements which are assumed to be relevant for the heat transfer within the furnace. All constructive parts, like screws, should be removed from the drawing. In the case of axi-symmetry, only one half of the geometry is needed. It may be also necessary already in this stage to identify potential gaps inside the furnace, which may have a severe impact on the resulting temperature field.

I have problems importing my CAD drawing. What shall I do?

CrysMAS can import .dxf files, which is a standard format for CAD drawings. You should export your drawing in the oldest possible .dxf format. Under Linux it sometimes occurs that a .dxf file can not be read by CrysMAS. In this case, you should open the drawing with an other CAD program, e.g., "qcad" and just save the file again. Usually, this fixes the problem.

How precise do I have to know the material properties?

If the material properties show a strong temperature dependence, it is mandatory that this behavior is defined for the corresponding property as well. On the other hand, you should never forget that you are just creating a model of reality - it will always be just an approximation. Please consider also, that other effects like thermal contact resistances may have a strong impact on the temperature field. Usually, this effect may be approximated by slightly changed values of the thermal conductivity.

Where can I get accurate data for the material properties?

A lot of data is provided in the Internet, especially on the web sites of the material suppliers. CGL has also quite a large material data base. On the other hand, some properties like the emissivity are not only material dependent, but strongly affected by the surface itself. In addition, these properties may also change during the operation of the furnace due to aging.