In this thesis we conducted thermal analysis of the prototype divertor element for W7-X stellarator, composed of the supporting structure, heat shield, interlayer and a cooling channel with water. We have analysed the temperature distribution at anticipated operating conditions. Based on the finite volume method, we performed the numerical analysis with the ANSYS CFX software. To verify the model of the diverter unit, we performed a sensitivity analysis of the computational mesh. We compared the simulation results with available experimental data to validate the selected boiling model. The simulations included different shielding materials, thermal loads and inclusion of a spiral insert in the cooling channel. In the model, we first adopted the model of a single-phase turbulent flow of water in the cooling channel based on the SST model, where we solved the coupled heat transfer for the solid and the liquid. Based on the parametric study, we found that the temperatures of the component materials do not reach critical values. At individual places, the temperature of the cooling channel wall can exceed the boiling temperature of water. Therefore, we also performed a two-phase flow simulation with the included boiling model. Results show that the amount of vapour generated by boiling is negligible and therefore does not pose a danger of transitioning into a film boiling.
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