Diffusion and convection in melts play an important role in most technological processes involving the liquid state. Many diffusion experiments in liquids suffer from additional transport induced by gravity-driven flow. Therefore, different research groups performed experiments under microgravity conditions aboard a space vehicle. But even there, diffusion measurements can be disturbed by residual accelerations and vibrations. To analyse this additional transport, model experiments using water as liquid were performed inside an airplane performing zero gravity flight manoeuvres. Because of the short duration of low gravity, the analogy between diffusive mass transport and the faster heat transport was used. The angle between the capillary and the direction of acceleration ranged between 0 deg and 90 deg. For oscillation amplitude of 100 mm, the increase of the frequency up to l Hz led to a slight increase of the additional transport. Experiments with l.7 Hz showed an additional transport of a 50% maximum. The effect of the angle between the capillary and the acceleration vector was within the experimental error limits.
Liquid metal diffusion experiments in microgravity - vibrational effects
Untersuchung der Diffusion flüssiger Metalle unter Mikrogravitation - Schwingungseinflüsse
Measurement Science and Technology ; 16 , 2 ; 336-344
2005
9 Seiten, 7 Bilder, 3 Tabellen, 28 Quellen
Article (Journal)
English
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