Experimental investigation on liquid-metal flow distribution in insulating manifold under uniform magnetic field

A presence of a strong external magnetic field can affect a flow distribution of a liquid-metal (LM) coolant in a fusion blanket, due to magnetohydrodynamic (MHD) effects. LM blankets have some manifolds, where the coolant flow from a single supply channel is distributed to multiple parallel channels. Since these manifolds have complex geometries, an interaction between induced axial electric currents and the magnetic field reorganizes the flow to be three-dimensional. A flow imbalance in such a complicated manifold affects heat removal performances, which is closely related to the blanket feasibility and safety. This study was performed to experimentally and numerically investigate a LM distribution in MHD flows in an electrically insulating manifold with changing the intensity and orientation of the magnetic field transverse to the flows. The flow passage employed in this study is a U-turn manifold consisting of an upward rectangular duct, a U-turn branching area, and two downward ducts with insulating walls. The gallium-indium-tin eutectic alloy (GaInSn) was employed as a working fluid. The present study shows that, as the magnetic field is applied more perpendicularly with respect to the U-turn, much amount of the fluid flows in the inner downward channel than that in the outer one.