The Selectable Optical Diagnostics Instrument - Influence of VIbrations on DIffusion of Liquids (SODI-IVIDIL) investigation studies the influence of controlled vibrations on diffusion in liquids in the absence of buoyant convection (transfer of heat by movement) in microgravity. These studies represent part of a series of investigations on the International Space Station (ISS) studying how heat and particles move through liquids in microgravity. This investigation provides additional data for applications to fields in mineralogy and geophysics for predictions about the locations of natural resources beneath the Earth's surface.Principal Investigator(s)
Verhaert Design and Development, Antwerp, , Belgium
European Space Agency (ESA)Sponsoring Organization
Information PendingResearch Benefits
Information PendingISS Expedition Duration:
March 2009 - March 2010Expeditions Assigned
19/20,21/22Previous ISS Missions
The microgravity environment is a unique situation 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.
The SODI-IVIDIL experiment investigates 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.
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 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.
A total of 55 experimental runs were successfully completed over the course of three months from October 2009 to January 2010. Initial analysis focused on the evolution of the liquid's concentration field both with and without imposed vibration. In the absence of vibration, there was no movement in the system and the concentration field mirrored the structure of the temperature field. However, in the presence of external vibration, more sophisticated flow patterns emerged (Mazzoni et al. 2010).
Additionally, experimental data from the concentration profiles was compared with numerical predictions. In the absence of vibration, the concentration profile was linear and in agreement with the predicted profile, which suggested that g-jitter (residual vibration) had little effect on diffusion. However, high frequency imposed vibrations did have an effect on diffusion, as seen when the concentration profile deviated from the linear profile under the influence of a relatively weak vibration (Mazzoni et al. 2010).
A closer look was taken at the effect of g-jitter on diffusion processes after the conclusion of each experiment. During the nominal, or quasi-steady, vibration regime of the ISS, g-jitter was not observed to affect diffusion in experiments run without imposed vibrations. These results were duplicated when the experiments were repeated with large time lags and different temperature gradients. Furthermore, the experimental results were in agreement with numeric simulations. However, perturbations were evident in experiments without imposed vibrations that ran during the non-nominal, or vibratory/transient, regime, the zone during which events such as orbit correction, docking, or undocking occur. SODI-IVIDIL was the first successful on-orbit experiment to characterize the effect of onboard g-jitter (Shevtsova et al. 2011).
The coefficients of diffusion and thermodiffusion were determined numerically and experimentally for a mixture of 10% isopropanol and 90% water with a 5 Kelvin (K) temperature gradient and no imposed vibration. Repeatable experimental results were in close agreement with numerical predictions. For water mass factors of 0.5 and 0.9, both the diffusion and thermodiffusion, or Soret, coefficients obtained from SODI-IVIDIL are in agreement with other experimental and literature values. The agreement between experimental and predicted results shows that both the numeric code and onboard method of measurement are successful in both the prediction and measurement of the diffusion and thermodiffusion coefficients. The obtained results provide benchmark values for future diffusion experiments in the intermediate and water-rich concentration regimes (Shevtsova et al. 2011, Mialdun et al. 2012).
The results from IVIDIL shed light on the complex mechanisms behind vibration induced convection and provide useful insight on how to control fluids in space to support future physical and life science experiments (Mazzoni et al. 2010).
Shevtsova V, Lyubimova T, Saghir Z, Melnikov D, Gaponenko Y, Sechenyh V, Legros J, Mialdun A. IVIDIL: on-board g-jitters and diffusion controlled phenomena. Journal of Physics: Conference Series. 2011; 327: 1-10. DOI: 10.1088/1742-6596/327/1/012031.
Mazzoni S, Shevtsova V, Mialdun A, Melnikov D, Gaponenko Y, Lyubimova T, Saghir Z. Vibrating liquids in Space. Europhysics News. 2010; 41(6): 14-16. DOI: 10.1051/epn/2010601.
Shevtsova V, Mialdun A, Melnikov D, Ryzhkov I, Gaponenko Y, Saghir Z, Lyubimova T, Legros J. IVIDIL experiment onboard ISS: thermodiffusion in presence of controlled vibrations. Comptes rendus de l'Academie des sciences Mecanique. 2011; 339: 310-317. DOI: 10.1016/j.crme.2011.03.007.
Ahadi A, Saghir Z. Transient Effect of Micro Vibration from Two Space Vehicles on Mixture During Thermodiffusion Experiment. Microgravity Science and Technology. 2013 02/06/2013; epub. DOI: 10.1007/s12217-013-9338-9.
Shevtsova V, Melnikov D, Legros J, Yan Y, Saghir Z, Lyubimova T, Sedelnikov G, Roux B. Influence of vibrations on thermodiffusion in binary mixture: A benchmark of numerical solutions. Physics of Fluids. 2007; 19. DOI: 10.1063/1.2409622.