Experimental investigation of liquid metal MHD flow entering a flow channel insert

Insulating flow channel inserts (FCI) in ducts of liquid metal blankets decouple electrically the fluid domain from the conducting thick-walled structure. They interrupt current paths across well-conducting walls and thereby reduce significantly magnetohydrodynamic (MHD) pressure drop. Pipe flow of an electrically conducting liquid metal entering a region where walls are covered by a FCI is investigated experimentally under the influence of a strong uniform magnetic field. The abrupt change in wall conductivity leads to 3D MHD effects that are studied by measuring pressure and electric potential distribution along the duct wall. It is shown that FCIs may reduce pressure drop by at least one order of magnitude but 3D effects at the entrance of FCIs may reduce the efficiency of the insulating inserts by some degree.