A liquid metal magnetohydrodynamic duct flow with sudden contraction in a direction perpendicular to a magnetic field

• A liquid metal MHD duct flow with sudden contraction is numerically investigated.
• The interdependency of the flow variables is clearly investigated.
• The results show large-scaled loops of the current passing through the duct walls and fluid region.

This study numerically examines three-dimensional liquid metal (LM) magnetohydrody-namic (MHD) flows in a rectangular, electrically-conducting duct with sudden contraction in a direction perpendicular to a uniform magnetic field. Though diverse analytical, experimental and numerical studies on MHD duct flows are performed, reports dealing with detailed flow characteristics of LM MHD flows in a rectangular duct with sudden contraction in a direction perpendicular to a uniform magnetic field are hardly found. In the present study, with the use of commercial software CFX code, the flow velocity, pressure, Lorentz force, current and electric potential in the MHD duct flow are obtained for flows with two different Hartmann numbers (1000 and 300) with fixed Reynolds number. The interdependency of the flow variables is considered in the discussion of the MHD duct flows with sudden contraction. The results show that large-scaled loops of the current passing through the duct walls and fluid region are created in the LM MHD flow, where the forward-facing wall serves as the path of the returning current that is induced in the fluid region.