Experimental and Numerical Analysis of the Deformation of a Liquid Aluminum Free Surface Covered by an Oxide Layer During Induction Melting

In an induction furnace, as a result of electromagnetic forces, the free surface of a liquid aluminum bath deforms and takes the form of a dome. The oxide layer that forms spontaneously on the free surface of aluminum melts may also influence the deformation by exerting an additional friction force on the metal. A non-intrusive experimental technique-Structured Light Fringe Projection-was used to measure the complete surface deformation and its fluctuations, for a varying set of operating parameters-inductor current intensity and initial liquid metal filling level inside the crucible. For an axisymmetric geometry, numerical simulations were carried out to calculate in a single framework: (i) the electromagnetic forces using the A-V formulation, (ii) the free surface deformation using the Volume of Fluid method, and (iii) the turbulent stirring of the metal using a RANS-based k-omega model. The friction force due to the oxide layer was modeled by imposing a pseudo-wall condition on the free surface, which makes the interfacial velocity very small compared to the average liquid metal pool velocity. A marked impact on the dome height due to applied friction force is observed. Finally, comparisons between the predicted and measured domes are presented.