MHD flows in a U-channel under the influence of the spatially different channel-wall electric conductivity and of the magnetic field orientation

Three dimensional magnetohydrodynamic (MHD) flows in a U-channel formed by inlet-, connecting- and outlet-channel are numerically examined with CFX code in the current research. The impacts of the flow velocities, the Hartmann numbers, the spatially changing channel-wall electric conductivity and of the magnetic field orientation on the MHD flow features are studied. Here, considered are the situations where the inlet-channel-wall electric conductivity is changed, while the connecting- and outlet-channel-wall electric conductivity is fixed. Velocity, pressure drop, current density and electric potential are analyzed in the present study. The highest value of velocity is observed in the right-angle segments. Typical “M-type” velocity profiles can be obtained only when the magnetic field and the main flow plane are transverse to each other, while the “M-type” velocity profile may not obtained when the magnetic field intensity is very low. The pressure drop decreases when the inlet channel-wall electric conductivity decreases, and it also decreases with the decreasing of the flow velocity and of the Hartmann number. When the magnetic field is parallel to main flow, the lowest pressure drop can be observed as the channel-wall electric conductivity of the inlet channel is the lowest. With the lower pressure drop, the mechanical stress of the duct can be minimized.