EPJ E Colloquium - European Space Agency experiments on thermodiffusion of fluid mixtures in space

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Published on 11 July 2019

Diffusive processes are ubiquitous in daily life and in natural processes, playing a key role in the transformation and mixing of fluid mixtures, and there is considerable scientific and industrial interest in such mixing processes. One consequence of diffusion is the development of non-equilibrium fluctuations in liquid mixtures, particularly when fluids are exposed to a thermal gradient. This is easier to observe in weightlessness, as gravity dampens this phenomenon on Earth especially for large fluctuations.

A new Colloquium paper published in EPJE describes the European Space Agency (ESA) experiments devoted to the study of thermodiffusion of fluid mixtures in a microgravity environment, where sedimentation and convection do not affect the mass flow induced by the Soret effect. It first describes the experiments performed on binary mixtures in the IVIDIL and GRADFLEX experiments. Then, further experiments on ternary mixtures and complex fluids performed in DCMIX and planned in the context of the NEUF-DIX project are presented. Finally, details are given of the multi-component mixtures studied in the SCCO project.