Liquid Metal Cleanliness Analyzer (LiMCA) in Molten Aluminum
Mei Li, Roderick I. L. Guthrie
A mathematical model was developed to describe the motion of inclusions within melts of aluminum passing through the electric sensing zone (ESZ) of a LiMCA (Liquid Metal Cleanliness Analyzer) system. The fluid flow field within the ESZ was obtained by solving the Navier-Stokes equations. The trajectories of entrained particles were calculated using the equations for motion of particles. The motion of particles within the parabolic shaped ESZ orifice was shown to be affected by particle conductivity, density and size. The numerical results prove that particles in molten aluminum are distinguishable by LiMCA system. On the other hand, the study of the fluid flow generated during the "conditioning operation" (corresponding to high amperage transiently passing through the ESZ) suggests that the dramatically increased fluid velocity thereby generated near the sidewalls of the ESZ during the current surge helps to clear any build-up of the inclusions prior to a sampling of inclusions within melts of aluminum.