RESUMO
The Soret coefficients of a set of ternary systems of 1,2,3,4-tetrahydronaphthalene (THN), isobutylbenzene (IBB), and n-dodecane (nC12) at 298.15 K were measured under microgravity condition aboard the International Space Station in the frame of the DCMIX1 experiment. The present work includes a comprehensive study of possible data processing sequences for the interpretation of interferometric Soret experiments in ternary systems. Several data processing methodologies are discussed. A significant concentration dependence of the Soret coefficients is observed. In the present study, we have obtained large and positive values for THN and negative ones for IBB in all investigated systems. A linear relation between the Soret coefficients of two components is derived for each system and allows validating experimentally the coefficients measured in other experiments.
RESUMO
The paper is devoted to processing the data of DCMIX 1 space experiment. In this experiment, the Optical digital interferometry was used to measure the diffusion and Soret coefficients in the ternary mixture of 1,2,3,4-tetrahydronaphthalene, isobutylbenzene and n-dodecane at mass fractions of 0.8/0.1/0.1 and at 25°C. The raw interferometric images were processed to obtain the temporal and spatial evolution of refractive indices for two laser beams of different wavelengths. The method for extracting the diffusion and thermal diffusion coefficients originally developed for optical beam deflection was extended to optical digital interferometry allowing for the spatial variation of refractive index along the diffusion path. The method was validated and applied to processing the data for Soret and diffusion steps in 5 experimental runs. The obtained results for the Soret coefficients and one of the eigenvalues of diffusion matrix showed acceptable agreement within each step. The second eigenvalue was not determined with sufficient accuracy.