Numerical investigation of liquid metal flows in rectangular sudden expansions

Three-dimensional magnetohydrodynamic flows in sudden expansions of rectangular channels with walls of finite electric conductivity have been investigated. The used numerical tool, based on an extended version of the commercial code CFX, gives accurate results up to Hartmann numbers Ha≤1000Ha≤1000. For stronger magnetic fields an asymptotic-numeric approach has been used. The results of the study show that for moderate magnetic fields vortical recirculations form behind the expansion. They are, however, suppressed for sufficiently high Hartmann numbers. Moreover, regions with very small velocities may appear. The analysis highlights also that inertial effects become smaller with increasing the interaction parameter N, but even for large N an inertial influence is still present. The additional pressure drop caused by the three-dimensional flow at the expansion and the flow partitioning between cores, internal and side layers have been analyzed in detail. Some of the main outcomes are summarized in this paper.