Measurement of solute diffusivity in electrically conducting liquids

摘要

The use of a magnetic field in the measurement of diffusion coefficients in liquid metals or semi-conductors is analyzed. Previous studies have demonstrated the disturbing influence of buoyancy-driven convection on the species transport in the shear-cell technique. A theory of effective diffusivity was proposed to account for the convective part of the transfer (GBD95). The idea developed her is to combine this effective diffusivity with the Lorentz electromagnetic damping of convection. The expected influence of the magnetic field is that the convective contribution should scale as Ha~(-4). Experiments were carried out and, for a small convection level, this magnetic influence was confirmed. It is suggested that a strong steady magnetic field could enable the precise measurement of liquid metal alloys diffusivities. The present analysis gives the required magnetic field magnitude.