Speaker
Description
In blankets for future fusion reactors, liquid metals have been chosen as breeding material, heat carrier and neutron multiplier. The use of electrically conducting fluids in a magnetic environment comes with the need of investigating their magnetohydrodynamic (MHD) interaction with the imposed magnetic field. The prediction of MHD phenomena for the development of liquid metal blankets requires validated reliable computational tools. With the purpose of obtaining benchmark data, an experimental campaign has been initiated at the Karlsruhe Institute of Technology by using the MaPLE PbLi loop. The latter is equipped with an electromagnet that can provide a magnetic field up to 1.8T and is fitted with a hydraulic system that enables tilting of the magnetic gap between ± 90°. This allows studying flows oriented at any angle with respect to gravity within a horizontal magnetic field.
Recent studies of magneto-convection in simplified geometries showed the occurrence of instabilities with high-amplitude temperature fluctuations that could lead to large thermal stresses in the wall (Zikanov et al. 2019). Moreover, the occurrence of magneto-convection can significantly affect mass (corrosion) and heat transfer in the liquid metal.
In order to improve the understanding of the effect of buoyancy on MHD flows, an experimental test section has been manufactured that features a square electrically and thermally conducting duct in which a part of the lower wall is uniformly heated. The magnetic field along the channel axis is uniform in a central portion of the duct, and it reduces gradually to zero at the entrance and exit of the magnet. With the aim of supporting the design of this experiment, identifying the best location for measurement sensors, and describing the main physical phenomena, 3D numerical simulations are performed for different flow parameters.
