Study on the impacts of pressure equalization slots on MHD flow and safety of FCI in DCLL blanket

For a Dual Coolant Lead Lithium (DCLL) blanket, in order to reduce the pressure difference between inner and outer area of flow channel insert (FCI), which accounts for the stresses in FCI, the pressure equalization slots (PES) are proposed. In the present work, we aim at performing a direct simulation of the magneto-thermal-fluid-structure multi-physical fields in the DCLL blanket, with PES or not, by a coupled computing platform including CFD and the finite element method (FEM), to study the pressure field, velocity field, temperature field and deformation and stresses of FCI. A consistent and conservative scheme and PISO method on an unstructured collocated mesh are employed to solve the incompressible Navier-Stokes equations with the Lorentz force included. The FEM is applied to investigate the thermal strains and stresses of FCI structure. The results show that: (1) inserting FCI with low electrical conductivity and low thermal conductivity, the MHD pressure drop can be reduced and the heat transfer efficiency can be improved; (2) PES does not contribute significantly to pressure equalization. In addition, for case with PES, some potential structural failures and other problems would be caused, such as stress concentration; (3) for the case with PES, although the exit temperature of liquid metal is decreased, the heat transfer efficiency is increased and the max temperature of the first wall (FW) and the temperature difference across FCI wall are decreased.