Soret and Diffusion Coefficients Measurement for Binary and Ternary Mixtures on Board the International Space Station Using SODI Apparatus

Amirhossein Ahadi

doi:10.32920/14660373

Abstract

<p>Thermodiffusion or Soret effect is a heat and mass transfer phenomenon in a non-isothermal liquid and gas mixtures. This phenomenon is more pronounced in oil fields, usually due to the porous environment. A precise and better understanding of the thermodiffusion phenomena in multi-component mixtures results in a more accurate modeling of oil reservoirs. Accordingly, the main objective of this study is to investigate the thermodiffusion phenomenon in the multicomponent mixtures. In order to achieve this objective, two series of thermodiffusion experiments conducted on board the International Space Station (ISS) using the SODI (Selectable Optical Diagnostics Instrument) facility were analyzed. The first series of experiments aimed to study the effects of the forced vibration on the Soret phenomena. The experimental mixture was water and isopropanol with different compositions subjected to various temperature gradients normal to the vibrations. Results revealed maximum separation for the case with the minimum vibration and the lower temperature gradient; however, a linear relationship between Gershuni number and maximum separation was not found. On the other hand, the second series of experiment was aimed to the measurement of the diffusion coefficients of selected ternary mixtures. Mixtures of tetrahydronaphthalene-isobutylbenzene-dodecane at five different compositions were hosted in the DSC (Diffusion and Soret Coefficient) cell array. Thus, the Soret diffusion coefficients and the molecular diffusion coefficients of the mentioned hydrocarbon mixture at five different compositions have been reported. To process the results of these experiments an advance image processing technique was developed and implemented in an application with GUI (Graphical User Interface) for the Mach-Zehnder interferometer (MZI). Then, the application of the windowed Fourier transformation (WFT) to analyze the heat and mass transfer problem using the MZI setup is proposed. Results show that the WFT noticeably improves the measurement of concentration. This improvement is more evident for the ternary. It was shown that about 10% underestimation of the Soret coefficient would be resulted; if an accurate determination of the thermal time for the MZI is not used. The reliability and the repeatability of the MZI apparatus on board ISS to study thermodiffusion for binary and ternary mixtures were shown.</p>

Highlights

Introduction and MotivationsThermodiffusion, called the Soret effect, is a phenomenon involving heat and mass transfer in a liquid, or a gas due to a temperature gradient
A new formulation to calculate the thermal relaxation time for the Soret effect experiment by means of Mach-Zehnder interferometry was proposed for the negative Soret effect, and an experimental approach was provided for measurement in the case of the positive Soret effect
For both negative and positive Soret effects, it was demonstrated that the precise thermal time for Mach-Zehnder interferometry (MZI) must not exceed more than 40 % of L2/ χ

Summary

Introduction

Thermodiffusion, called the Soret effect, is a phenomenon involving heat and mass transfer in a liquid, or a gas due to a temperature gradient It is important in oil exploration and in optimal oil recovery since it causes diffusion fluxes in hydrocarbon reservoirs. Thermodiffusion or Soret effect is a heat and mass transfer phenomenon in a non-isothermal liquid, gas or even solid mixture due to a local temperature gradient[2,63,64] This phenomenon is more pronounced in oil fields, usually due to the porous environment [4,5,41,156]. A precise and better understanding of the thermodiffusion phenomena in multi-component mixtures results in a more accurate modeling of oil reservoirs and it may reduce the number of required wells, which approximately costs about $20 million/well Before this observation, Soret coefficient values were usually ignored in oil recovery investigation [27]. Thermodiffusion has critical applications in environment discovery [11], microfluidic applications [12,13], particle motion in microfluid devices[14] and life science sector in the field of DNA studies[15– 17]

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