A GENERAL COMPUTATIONAL\ud APPROACH FOR MAGNETOHYDRODYNAMIC\ud FLOWS USING THE CFX\ud CODE: BUOYANT FLOW THROUGH A\ud VERTICAL SQUARE CHANNEL

摘要

The buoyancy-driven magnetoconvection in the cross\udsection of an infinitely long vertical square duct is investigated\udnumerically using the CFX code package. The\udimplementation of a magnetohydrodynamic (MHD) problem\udin CFX is discussed, with particular reference to the\udLorentz forces and the electric potential boundary conditions\udfor arbitrary electrical conductivity of the walls.\udThe method proposed is general and applies to arbitrary\udgeometries with an arbitrary orientation of the magnetic\udfield. Results for fully developed flow under various thermal\udboundary conditions are compared with asymptotic\udanalytical solutions. The comparison shows that the asymptotic\udanalysis is confirmed for highly conducting walls\udas high velocity jets occur at the side walls. For weakly\udconducting walls, the side layers become more conducting\udthan the side walls, and strong electric currents flow\udwithin these layers parallel to the magnetic field. As a\udconsequence, the velocity jets are suppressed, and the core\udsolution is only corrected by the viscous forces near the\udwall. The implementation of MHD in CFX is achieved.