Development of a Numerical Tool to Simulate Magnetohydrodynamic Interactions of Liquid Metals with Strong Applied Magnetic Fields

In the framework of the study of a European helium cooled lead lithium blanket concept for ITER, numerical tools are developed to complement experimental activities. Full capability to simulate numerically the global magnetohydrodynamic flow and pressure distributions resulting from the interaction of the liquid metal with the strong plasma confining magnetic field is not achieved yet. Calculations should support the selection and validation of physical models for 3D coupled phenomena, like magneto-convection, as well as for corrosion and tritium permeation processes. Moreover, simulations help to interpret measurement data and to enhance the development of extrapolation procedures from small-scale experiments to a DEMO reactor.

The present paper summarizes the mathematical algorithm and modeling requirements for accurate predictions of liquid-metal flows under very intense magnetic fields in geometries with arbitrary electric conductivity of the walls. The Lorentz force term and additional equations determining electric current density and potential have been introduced in a consistent and conservative way into the existing hydrodynamic open source code OpenFOAM. The use of non-orthogonal corrections leads to a significant improvement of the MHD code at fusion relevant strong magnetic fields. The discussion focuses on benchmark problems used to validate the new developed tool and on the treatment in OpenFOAM of MHD flows in geometries with walls of finite electric conductivity. According to the authors' knowledge, the implementation of this capability in this open source code has not been reported so far in other references.