Design of a flexible liquid metal loop for investigation of MHD flows related to fusion blanket applications

In order to investigate fundamental features of magnetohydrodynamic (MHD) channel flows a closed liquid-metal circuit has been designed and manufactured in the MEKKA laboratory at the Karlsruhe Institute of Technology. This loop, which uses GaInSn as a model fluid, provides a flexible tool for studying properties of MHD flows and testing techniques for measuring electric potential and velocity for later use during experiments in ITER test blanket modules. Of particular interest is for instance the investigation of the stability of laminar MHD duct flow, the onset of turbulence and formation of quasi-2D turbulent structures as expected in intense magnetic fields. The main features of the loop are described and some numerical results used during its design are outlined.