Numerical modelling of multiphase flow and heat transfer within an induction skull melting furnace

A numerical and experimental study of free surface motion and heat transfer within an induction skull melting furnace is discussed in this paper. The developed computational domain was three-dimensional with defined periodic boundary conditions, which correspond to the segmented geometry of an actual cold crucible. An electromagnetically driven flow and temperature field within the numerical domain was simulated on the basis of two-way coupling of electromagnetic and fluid dynamic fields. To predict the electromagnetic field, a set of Maxwell's equations was solved. Then, the information regarding the Lorentz force and Joule heat distributions was transferred to a fluid dynamics submodel. These fields appeared as source terms in the momentum conservation and energy equations, respectively. The multiphase flow was considered turbulent with a free surface. It was simulated using a realizable k-ε model and a volume of fluid approach. Moreover, to consider the radiation heat transfer, the discrete ordinates method was applied. The proposed coupled mathematical model was compared with experimental results obtained from an industry induction skull melting furnace. The model validation clearly showed high accuracy in the discussed numerical model despite the applied simplifications. The shape of the free surface obtained from the computational model was within the standard deviation of the measurements, with a relative error under 4%. The charge temperature, after achieving steady state, was predicted with very high accuracy; however, the heating process was slightly underestimated. Finally, a qualitative comparison for the lower part of the meniscus was also performed. In that region, characteristic tooth-shaped peaks in the connection between the charge and crucible walls were identified for both experimental and numerical analyses.