Modeling of Fluid Flow Effects on Experiments Using Electromagnetic Levitation in Reduced Gravity

Electromagnetic levitation experiments provide a powerful tool that allows for the study of homogeneous nucleation, solidification and growth in a containerless processing environment. However, in these experiments it is important to understand the magnetohydrodynamic flow within the sample and the effects that this fluid flow has on the experiment. A recent solidification study found that aluminum-nickel alloy samples have an unusual growth response to the degree of undercooling. These aluminum-nickel alloys experienced a decrease in the growth velocity as the initial undercooling deepened instead of the expected increase in solidification velocity with deepening undercoolings. Current work is exploring several different theories to explain this phenomenon. Distinguishing between several of these theories requires a comprehensive understanding of the behavior of the internal fluid flow. USTIP has done flow modeling to support this and multiple other collaborators on ISS-EML. The fluid flow models presented provide critical insights into the nature of the flow within the aluminum-nickel alloy experiments conducted in the ISS-EML facility. These models have found that for this sample the RNG k-ε model should be used with this sample at temperatures greater than 1800 K and the laminar flow model should be used at temperatures lower than 1600 K.