Nuclear Materials and Energy (Mar 2021)
Modeling of liquid lithium flow in porous plasma facing material
Abstract
Flowing liquid lithium can, in principle, create a renewable surface interacting with the plasma, providing protection for the underlying solid substrate. Recent experiments [1] showed that liquid lithium supplied through a porous medium can limit the plasma facing surface temperature, even at high heat flux values in excess of 10 MW/m2. The use of new 3D printing techniques allows creation of plasma facing components that supply liquid lithium through capillary channels. Numerical analysis can be used to develop and optimize porous plasma facing component using virtual prototyping. The present contribution introduces a numerical model of liquid metal flow in a porous structure, interacting with the plasma. The model uses computational fluid dynamics (CFD) to model a flow through a complex 3D geometry including magneto-hydrodynamics (MHD) effects. The CFD set-up covers the liquid metal, plasma and solid structures, simultaneously, connected by realistic interfaces. Small scale interface structures are modeled separately to obtain a self-consistent interface functions. Customized version of the general-purpose CFD is used to handle complex 3D geometries, and efficient pre- and post-processing. MHD is introduced using the magnetic vector potential approach, allowing precise fluid–solid interface treatment. Special stabilization procedures were derived and applied to improve convergence of the momentum balance equations with source terms due to Lorentz force and surface tension. Conjugate heat transfer analysis was performed in the plasma, liquid metal and solid components. The customized code was validated using analytical results for high Hartmann number flow. Results of the validation and numerical analysis of liquid lithium plasma facing components using porous walls will be presented.
