| Abstract Scope |
Al-, Fe-, and Ni-based metallic alloys were processed in microgravity using electromagnetic levitation aboard the ISS (ISS-EML) and during parabolic flights (TEMPUS) as part of ESA projects NEQUISOL, CCEMLCC, and THERMOPROP. Density, surface tension, and viscosity were measured using the oscillating drop method, with droplet motion captured by a high-speed camera and temperatures recorded via infrared pyrometry. Significant discrepancies were observed between the measured and expected viscosities for the Al-based and Ni-based alloys. These deviations are attributed to excessive excitation from heater pulses, sample rotation, and internal convective flows, which all contribute to deviation from the theoretical assumptions of small-amplitude linear oscillations. To assess the influence of these perturbations, we applied Xiao and Lohöfer’s analytical and MHD models, alongside COMSOL Multiphysics simulations. The study examines how such disturbances lead to viscosity misestimation and proposes improved approaches for accounting for nonlinear and parasitic effects in future measurements. |