Modelling of Liquid Metal Duct and Free-Surface Flows using CFX

摘要

Liquid metal free-surface flows provide an option of a renewable surface for heat absorption, removal of impurities, and eliminating the problems of erosion and thermal stresses. In a tokamak liquid metal flows through a strong magnetic field, which results in a magnetohydrodynamic (MHD) interaction. For a free-surface flow the MHD interaction may be even more important than for the duct flows in blankets, because the electromagnetic forces may significantly deform the free-surface and thus make it unfavourable for heat extraction. The MHD-related problems for the free-surface flows have been reviewed in. Among the most important ones are the effects of nonuniform magnetic fields, inertia, surface tension, wettability and roughness of walls on both the jet/drop shape and trajectory. For modelling ordinary hydrodynamic flows several commercial codes are available, such as CFX, FLUENT, FLOW-3D, etc. Although most of them do not model MHD flows automatically, they can be modified using user-defined subroutines to include the body forces, such as the Lorentz force, and couple the momentum equations with the other MHD equations. The aims of this report are: to summarise the first steps in the development of the extension of CFX for modelling MHD flows, to present the results of testing the code on several benchmark problems, and to present the description of the code for further reference.