Numerical simulations of buoyant magnetohydrodynamic flows using the CFX code

The buoyancy-driven magnetoconvection in a vertical square duct is investigated numerically using the CFX package. The implementation of an MHD problem in CFX is discussed, with particular reference to the Lorentz forces and electric potential boundary conditions for arbitrary electrical conductivity of the walls. The method proposed is general, and applies to arbitrary geometries with an arbitrary orientation of the magnetic field. Results for fully developed flow under various thermal boundary conditions are compared with asymptotic analytical solutions. The comparison shows that, for higher values of the wall conductivity, the asymptotic analysis is confirmed, and high velocity jets occur at the side walls. For lower values, the side layers become better conducting than the side walls and high current jets appear parallel to the side walls. As a consequence, velocity jets don't occur anymore and the core solution is corrected just by viscous forces at the wall. The capability of CFX in describing properly an MHD problem is proved. (orig.)Available from TIB Hannover: ZA 5141(6354) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman