Liquid Metal Flow Through a Right Angle Bend in a Strong Magnetic Field

Abstract

In designing a self-cooled liquid metal blanket based on the poloidaltoroidal flow concept, the magnitude of the MHD pressure drop and the character of the velocity distribution in the first wall coolant channels, that result from 3-dimensional MHD effects associated with the required right angle bends in the coolant flow, represent important design issues. To address these issues and to verify the relevant models used in the design, a joint MHD-experiment was conducted by Argonne National Laboratory (AND and Kernforschungszen-trum Karlsruhe (KfK). The test article was designed and built at ANL, and the experiments were performed at KfK’s MEKKA facility using a 3.6 Tesla superconducting solenoid magnet and a eutectic sodium potassium alloy working fluid. In the experiments, detailed voltage and pressure distributions on the duct walls and voltage distributions within the liquid metal were measured under a variety of Hartmann numbers and interaction parameters. Representative results from these measurements are presented and compared to analytical predictions valid for very high interaction parameters (inertialess flow). Results indicate that deviation between analysis and experiment is confined to the immediate vicinity of the right angle sharp corner and that, for fusion blanket conditions, the 3-dimensional pressure drop in the radialtoroidal bend of an electrically separated single channel is small compared with the pressure drop of the radial flow.