Contribution to the benchmark for ternary mixtures: Measurement of diffusion and Soret coefficients in 1,2,3,4-tetrahydronaphthalene, isobutylbenzene, and dodecane onboard the ISS

Abstract

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.

Impact of Thermodiffusion on the Initial Vertical Distribution of Species in Hydrocarbon Reservoirs

“…Although noticeable progresses have been made during the last twenty years, see Assael et al (2014) and references therein, especially on ternary mixtures both theoretically (Firoozabadi et al 2000;Kempers 2001;Galliero et al 2003) and experimentally (Leahy-Dios et al 2005;Bou-Ali et al 2015) more work is necessary. Micro-gravity experiments are one possible way to provide further data on thermodiffusion in multicomponent mixtures (Georis et al 1998;Van Vaerenbergh et al 2009;Touzet et al 2011;Khlybov et al 2015). They are particularly interesting because they provide, by default, experimental conditions free of convection effect.…”

Effect of gravity orientation in the study of thermodiffusion

“…Although a linear concentration profile was expected for a non‐inclined cell, the regions near the hot and cold walls experienced nonlinear concentration profiles that were cropped out during image processing and only the linear parts were used to calculate the Soret coefficient. These nonlinearities near the upper and lower boundaries were likely related to the concentration differences lost during the thermal time …”

Results of the DCMIX1 experiment on measurement of Soret coefficients in ternary mixtures of hydrocarbons under microgravity conditions on the ISS

“…A movable two-wavelength interferometer, which can be moved to the selected cell, probes the primary cells. 33 The wavelengths of the laser diodes used are λ 1 = 670 nm and λ 2 = 935 nm.…”

“…Phase unwrapping is a well-known problem in interferometry, and many different algorithms have been proposed to remove the phase ambiguity. 45 In DP1, DP2, and DP3, a modified 40 version of the Itoh algorithm 46 was implemented; in DP 4 and 5, the wrapped phase images are of sufficient quality, the phase exhibit a strict horizontal alignment, and a one-dimensional sequential phase unwrapper was employed; 33 in DP6 and 7, the Costantini 47 algorithm was used. 48…”