关键词: 突扩, 导电管, 磁流体, OpenFOAM

Abstract: Liquid metal flow subject to a uniform magnetic field vertical to streamwise direction confined in a rectangular duct with 45° and 90° sudden expansion, and electrically conducting walls is numerically studied using magnetohydrodynamic (MHD) flow solver developed in OpenFOAM environment. Velocity distribution, induced electric current, pressure gradient and three-dimensional MHD effect are analyzed in detail. It shows that as external magnetic field is parallel to direction of duct expansion, velocity distribution is better in 45° sudden expansion duct than that in 90° expansion duct since there is no vortex at the expansion. With Hartmann number increasing, high velocity jets and intensive induced electric current cause a strong instability at the expansion. Instability grows to upstream of the expansion through induced electric current. As external magnetic field is vertical to expansion direction, induced electric current along streamwise direction is significant. With Hartmann number increasing, MHD pressure drop increases remarkably. Dimensionless pressure drop in fully developed duct is almost the same in different expansion duct as direction of applied magnetic field and Hartmann number are the same.

Key words: sudden expansion, conductive duct, magnetohydrodynamics, OpenFOAM