title: Temperature dependence of Soret and diffusion coefficients for toluene-cyclohexane mixture measured in convection-free environment.
abstract: We report on the measurement of diffusion (D), Soret (S(T)), and thermodiffusion (D(T)) coefficients in toluene-cyclohexane mixture with mass fraction of toluene 0.40 onboard of the International Space Station. The coefficients were measured in the range of the mean temperatures between 20 °C and 34 °C. The Soret coefficient is negative within the investigated temperature range and its absolute value |S(T)| decreases with increasing temperature. The diffusion coefficient for this system increases with temperature rising. For comparison, the temperature dependence of diffusion coefficient was measured in ground laboratory using counter-flow cell technique and revealed a good agreement with microgravity results. A non-direct comparison of the measured onboard Soret coefficients with different systems indicated a similar trend for the temperature dependent behavior. Unexpected experimental finding is that for this system the thermodiffusion coefficient D(T) does not depend on temperature.
authors.affiliation: MRC, CP165/62, Université Libre de Bruxelles, Av. F.D. Roosevelt, 50, B-1050 Brussels, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Mialdun
authors.affiliation: MRC, CP165/62, Université Libre de Bruxelles, Av. F.D. Roosevelt, 50, B-1050 Brussels, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Shevtsova