Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 38: Poster: Colloids and Complex Liquids

CPP 38.28: Poster

Mittwoch, 16. März 2011, 17:00–19:00, P2

Multicomponent diffusion in microgravity environment — •Matthias Gebhardt, Andreas Königer, and Werner Köhler — Physikalisches Institut, Universität Bayreuth

In particular transport processes in true multicomponent systems (n > 2) are still not fully understood and there is a lack of experimental data for ternary and higher mixtures. In many cases the Soret cell, where a liquid sample is placed between two differentially heated copper plates, is used in experiments. The absence of convection is crucial for purely diffusive heat and mass transfer. It is known that many liquids can exhibit negative separation ratios, i.e. heavier components segregate to the hot regions. In gravity fields this has a destabilizing effect on the system and can cause convective instabilities. Microgravity experiments (TRIMIX) are planned using the SODI facility onboard the ISS, which is equipped with a two-color Mach-Zehnder interferometer. We are performing accompanying ground based measurements using a two-color optical beam deflection technique. We provide first experimental results and discuss the influence of the refractive index dispersion relations on the feasibility of the experiments.