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Selectable Optical Diagnostics Instrument-Influence of VIbrations on DIffusion of Liquids (SODI-IVIDIL)
11.20.09

Overview | Description | Applications | Operations | Results | Publications | Images

Experiment/Payload Overview

Information provided courtesy of the European Space Agency (ESA) Brief Summary

The Selectable Optical Diagnostics Instrument?Influence of VIbrations on DIffusion of Liquids (SODI-IVIDIL) experiment will study the influence of controlled vibration stimulus (slow shaking) on diffusion in liquids in the absence of convection induced by the gravity field.

Principal Investigator

Information Pending

Co-Investigator(s)/Collaborator(s)

Information Pending

Payload Developer

Verhaert Design and Development, Antwerp, Belgium

Sponsoring Agency

European Space Agency (ESA)

Expeditions Assigned

|21|22|

Previous ISS Missions

Information Pending

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Experiment/Payload Description

Research Summary

  • The Selectable Optical Diagnostics Instrument-Influence of VIbrations on DIffusion of Liquids (SODI-IVIDIL) project aims at investigating the effects of vibrations on liquid diffusion. The International Space Station (ISS) has residual vibrations, also known as g-jitter. Although they seem to have a major impact on the measurement of the diffusion coefficient, very few studies have been carried out on this topic. The researchers plan to characterize the spectral influence of g-jitter. The objective of this experiment is to increase the understanding of the kinetic mechanisms influencing diffusion effects in the presence of vibrations.


  • SODI-IVIDIL will investigate the impact of vibrations on the measured thermal and isothermal diffusion coefficient in a controlled way. The measurements will be repeated at different amplitudes and frequencies in order to validate the results.


  • SODI-IVIDIL will aim to validate the measurement technique to be used by petroleum industries or in an ISS application program at a low residual gravity level. SODI-IVIDIL will also verify the numerical modelling of the vibration impact on the diffusion processes in the range 0.01-2.8 hertz.

Description

The microgravity environment is a unique tool for studying the behavior of liquids, since the reduced buoyancy force allows the observation of processes that are masked or biased by normal gravity. In particular, for binary and more complex fluid mixtures, accurate measurements of thermal and isothermal diffusion coefficients in ground based experiments are often perturbed by gravity, especially in the case of thermal diffusion, where the temperature difference applied to the sample may provoke parasitic convective flows. However, in real space experiments, the benefit of the free fall condition may be altered by residual gravity vibration (also known as g-jitter). It is caused by aerodynamic forces, onboard equipment, and in the case of manned platforms, by crew movements. Although it is recognized that g-jitter may have a major impact on diffusion and thermal diffusion measurements, very few experiments have been carried out in the past. Even if the overall forces caused by disturbances are relatively small (ranging from 10-2 to 10-6 times the normal gravity), the effect may be non-negligible for long duration experiments such as the ones that involve diffusion limited phenomena. The purpose of the SODI-IVIDIL project is to measure thermal and isothermal diffusion coefficients in binary systems subjected to controlled vibration under different values of amplitude and frequency. There exist a number of numerical codes to assess for studying the effect of residual gravity and vibration, but their reliability is difficult to assess due to lack of experimental investigations. The IVIDIL project should therefore provide reference data for the validation and testing of numerical codes.

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Applications

Space Applications

The SODI-IVIDIL experiment will investigate the effects of residual vibrations (g-jitter) on experiments involving diffusion in liquids. Researchers plan to characterize the spectral influence of g-jitter to increase the understanding of the kinetic mechanisms influencing diffusion effects in the presence of vibrations, therefore allowing for more successful science to be operated onboard ISS.

Earth Applications

Based on previous studies, scientists have developed numerical simulations to help understand oil behaviors in a given well. The SODI-IVIDIL experiment will allow scientists to confirm and refine the parameters of their models, leading to more accurate predictions about oil wells being considered for extraction.

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Operations

Operational Requirements

Downlink of data is required to quickly assess the integrity of the liquid sample and to characterize the thermal field imposed on the experimental cell. Residual gravity levels induced by controlled vibration stimulus will be measured with a companion cell filled with calibrated tracers. The 3D motions of the tracers will be reconstructed by digital holography (a technique that allows a digital, post process reconstruction of the whole experiment cell volume from a single image).

Operational Protocols

Crewmembers will install the SODI optical instrument and the IVIDIL experiment cell arrays (2 cell arrays each composed of 2 cells). After installation, the next step involves the optical processing of the liquid binary solution in two steps under the stimulus of controlled linear vibrations. In the first phase, a thermal gradient is imposed across the experimental cell, inducing a concentration difference due to the Soret effect. Then, once a steady state concentration gradient is reached, the temperature gradient is removed, causing the system to homogenize due to molecular diffusion processes. These processes should be repeated several times under various vibration frequencies and amplitudes, so that statistically relevant results can be derived. After processing the IVIDIL cells, the SODI instrument should be stowed.

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Results/More Information

Information Pending

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Related Web Sites

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Publications

Results Publications

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    Related Publications

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      Images

      imageImage of SODI-IVIDIL Cell Array. Image courtesy of ESA.
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      imageImage of SODI-IVIDIL Vibration Mechanism. Image courtesy of ESA.
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      imageImage of SODI facility without the IVIDIL Cell Array inside the Microgravity Science Glovebox (MSG). Image courtesy of ESA.
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      imageNASA Image: ISS020-E-041873: Robert Thirsk,Expedition 20/21 flight engineer,working with the Selectable Optical Diagnostics Instrument - Influence of VIbrations on DIffusion of Liquids (SODI-IVIDIL) experiment in the Microgravity Science Glovebox (MSG) in the Columbus module.
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      Information Provided and Updated by the ISS Program Scientist's Office
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