# 3.3. Tutorials¶

With the help of Elmer module the user can define his own finite element method problems and compute them. This section provides intructions on how to use Elmer Tools to create independent cases with user defined equations, boundary conditions, material properties, etc. Using finite element method, there are several key steps needed to be made before the computation is run:

• Defining the CAD model, used for analysis: First one has to define the physical boundaries of our problem. When preparing CAD model for the analysis, one has to be careful to remove unneccessary details, that could have bad effects on the meshing and the computation itself. If possible, one should remove all the details that don’t affect the computation too much. Such details could be holes, small components like screws and nuts, etc. On the other hand the user needs to be careful not to simplify the model too much, otherwise the accuracy of the result may be wrong.
• Meshing: Next step is to mesh the model. Here we have to choose the appropriate type of element and its size. The user can also define different subsections of the CAD model that can have different density of triangles.
• Defining the type of solver: With elmer one can solve different types of problems like Heat equation, Navier-Stokes equations, Thermomechanical problems, etc. In this step one has to define the proper type of solver and its properties.
• Defining material properties: Material properties are defined according to the defined solver. Materials are later assigned to the appropriate section of CAD model.
• Loading conditions: In this step one must define the boundary and initial conditions of the problem.
• Assigning properties to sections: In this step the user must assign boundary conditions and material properties to the subsections of the model.
• Computation: In the final step we can run the computation.

The goal of the graphical user interface is to simplify the usage of temperature calculation code. This is why user needs to define three key parameters in order for temperature calculation to be successful.

• VTK file: VTK file is the output file of Smiter power deposition calculation. The format of the vtk file is unstructured grid and contains information about one enhanced heat flux panel or normal heat flux panel.
• Type of panel: There are two possible types of panels in ITER tokamak. The first is enhanced heat flux panel and the other is the normal heat flux panel. Enhanced heat flux panel has maximum power deposition of $$4.7 MW/m^2$$ and consists of beryllium shield, CuCrZr support and SS316 base. Those subcomponents form hypervapotron, the component with highest thermal loading in the reactor. Normal heat flux panel consists of beryllium shield, CuC1 support, and two subcomponents made of CuCrZr and SS316. Biggest power deposition is $$2 MW/m^2$$.
• Position of panel: There is 18 panels in poloidal direction. Every one of them has its own inclination angle, that depend on the position of the panel in poloidal cross-section. In order to align the panel with the simplified model, one has to determine the position of the panel in poloidal cross-section.