Validity of quasi-2D models for magneto-convection

For applications in nuclear fusion reactors where magnetic fields are very strong, liquid metal flow in the core of ducts can often be regarded as inertialess and practically inviscid, while viscous effects are localized in thin boundary layers. The intense electromagnetic Lorentz forces, resulting from the interaction of induced electric currents and imposed magnetic field, tend to remove flow variations along magnetic field lines and they force the fluid to circulate mainly in planes perpendicular to the field. The established quasitwo dimensional (Q2D) magnetohydrodynamic (MHD) flow can be predicted by means of an approximate model by reducing the basic governing equations to a 2D problem by analytical integration along magnetic field lines. Such models have been applied in the past by numerous authors to investigate duct flow problems and magneto-convection. However, limitations of those Q2D approaches have never been systematically studied.