Numerical study of the effect of a magnetic field on corrosion of ferritic/martensitic steel in a turbulent PbLi flow

S. Saeidi - S. Smolentsev

Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 43-133 Engineering IV, Los Angeles, CA 90095-1697, USA

Abstract
The effect of a magnetic field on corrosion of ferritic/martensitic steel and the associated transport of corrosion products in a turbulent flow of lead-lithium (PbLi) eutectic alloy in a channel are studied numerically. The impact of the magnetic field strength and its direction for this mass transfer problem is analyzed with the aid of a mass transfer equation for dissolved corrosion products coupled with the magnetohydrodynamic (MHD) equations that utilize a special form of the K-ε model of turbulence, which takes into account effects of turbulence suppression by a magnetic field. Computations are performed for three orientations of the magnetic field, with respect to the main flow (streamwise, spanwise and wall-normal B-field) in the temperature range from 400 to 550^°C, which is of particular interest for fusion cooling applications. Changes in corrosion rate caused by MHD effects have been analyzed with regard to turbulence modification by a magnetic field and to formation of the Hartmann boundary layers at the walls perpendicular to the magnetic field. As demonstrated, for all three magnetic field orientations, decrease of the corrosion rate occurs as the magnetic field increases. However, a wall-normal magnetic field has a stronger effect on the reduction of the corrosion rate compared to the other two magnetic field orientations due to more intensive turbulence suppression. Figs 9, Refs 23.