Figure 3. The FastCast levitation melting and casting furnace in operation at ALD
and recent technical achievements of the FastCast demonstrator which is in operation at ALD.
The Novel Method For The Large- Scale Levitation Melting The new method applies two EM fields of different AC frequencies, whose field lines in the absence of a charge are horizontal and orthogonal in order to exert Lorentz forces also at the axis of the levitated sample. Therefore, the charge weight can be increased and the charge can be drip- and leakage-free melted. The method for EM levitation melting in horizontal fields has been validated by a series of experiments with small samples up to 40 g [5]. Today, numerical modelling is undisputedly a very powerful tool that can lead the development of new products from idea to final implementation in a significantly shorter time and cost-effectively way. For the
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further development and scale-up of the novel levitation melting method a numerical model for simulation of turbulent flow and free surface dynamics of liquid metal in EM fields has been developed and extensively verified [6]. Computation of EM induced flow and free surface dynamics is ensured by means of coupling between: • EM field and Lorentz force recalculation in ANSYS,
• Volume of Fluid (VOF) Large Eddy Simulation (LES) of a two-phase turbulent flow in FLUENT and
• a free surface shape filtering and reconstruction in CFD-Post.
At first, using the developed numerical model, the two-frequency EM levitation
melting furnace has
been designed to meet conditions for the levitation melting of 500 g of Aluminum. Following the simulation- aided design the melting unit has been
built. Experiments revealed excellent agreement with modelling results and proved the potential of the scale-up of the novel method [7].
ALD has decided to apply the “state- of-the-art” levitation melting system and advantages of the novel method for real investment castings with ceramic moulds and launched the FastCast project. Using numerical modelling the melting unit was further optimised (Figure 2) since the levitation melting of Ti- and Ni-alloys faced advanced requirements.
Combining all gathered simulation
results and ALD’s expertise in investment casting, a demonstrator furnace has been designed and manufactured (Figure 3). FastCast overcomes boundaries of conventional casting methods with ceramic or copper crucibles. Levitating in a magnetic field, the metal has no
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