Numerical analyses on liquid-metal magnetohydrodynamic flow in sudden channel contraction

Abstract

ABSTRACTThree-dimensional numerical calculations have been performed on the magnetohydrodynamic (MHD) flows through a rectangular channel with sudden contraction, particularly in order to estimate the pressure drop through the sudden contraction. The sudden contraction is in the directions both perpendicular and parallel to the applied magnetic field. The Hartmann number, the Reynolds number, and the magnetic Reynolds number were set to ∼100, ∼1000, and ∼0.001, respectively, in simulating laboratory conditions. The continuity equation, the momentum equation, and the induction equation were solved numerically. In the sudden contraction in the direction perpendicular to applied magnetic field, the loss coefficient takes a positive value in all the cases performed in this study, contrary to the expectation. This result is in contrast to that in the sudden expansion in the direction perpendicular to applied magnetic field, where the loss coefficient generally takes a negative value due to the MHD effect. In the sudden contraction in the direction of applied magnetic field, the loss coefficient takes a positive and large value in all the cases performed in this study. The loss coefficient generally becomes larger than that in the case of corresponding channel expansion in the direction of applied magnetic field.