IVIDIL : Influence of Vibrations on Diffusion in Liquids
Space experiment, on-board g-jitter, vibrational convection in liquids, diffusion and Soret coefficients, interferometry.
January 2004 – December 2011
Scientists from ULB have been studying (thermo)-diffusion in liquid mixtures since the first classical works by Professor Prigogine, Nobel Prize Winner. Now, these investigations are moving further - to the ISS. The international experiment IVIDIL has been conducted inside the ESA SODI Facility on board the Columbus laboratory on the International Space Station (ISS) from 5 October 2009 until 28 January 2010. Fruitful collaborations and great efforts of the scientific teams, payload developers and flight operation team have been rewarded by outstanding results from 55 experimental runs.
The knowledge of transport properties in liquid mixtures has important industrial applications, i.e. in oil recovery, crystal growth, material processing, etc. On the one hand precise measurements of transport coefficients under terrestrial conditions are often perturbed by buoyancy-induced flows. On the other hand, the benefits of the microgravity environment on the ISS can be altered by the onboard vibrations (also called g-jitters). The IVIDIL experiment has provided benchmark measurements of transport coefficients and clarified the role of the on-board perturbations. From the fundamental point of view, an important objective is the study of vibration-induced convection and, particularly, heat and mass transfer under vibrations. To hit these targets, a liquid sample in which thermo and molecular diffusion take place, is placed on a vibrating bench. The amplitude and the frequency of the vibrations are imposed at adjustable values.
These experiments were prepared by an International Science Team and coordinated by Prof. V. Shevtsova (MRC-ULB). The MRC team was responsible for the development and implementation of the experiment, while the numerical and theoretical support is shared between all participants (MRC, Ryerson University, Toronto, Canada and a Russian team from Perm). Numerical simulations of all the runs were performed prior to the flight; the experimental technique was tested and fine-tuned in Parabolic Flight experiments; the software for image processing was in-house developed. It allowed controlling the performance and analyzing the first results of the experiment in real time. The current running task is to process the thousands of images, which arrived on the ground on a flash disk, and to find explanation to those observations, which were not expected. The research group “Non-linear phenomena in fluids” (NLF) led by V. Shevtsova is extensively working on the project.
International Space Station (ISS):
Oct. 2009 - Jan. 2010
The experiments performed on the ISS and in Parabolic Flights (PF) provided the first experimental evidence of thermo- and soluto-vibrational convection in reduced gravity environment. The PF experiments showed that the flow develops in parallel planes formed by the direction of vibration and temperature gradient. The flow patterns in all such planes are similar, so the total flow can be described as quasi two-dimensional. In the ISS experiments the concentration of liquid mixture contributes to the density variation in addition to the thermal effect. Unlike to PF the images from the ISS experiments reveal 3D flow structure. The science team works on the theoretical model for the explanations of these findings. Besides, experiments on the ISS show that for the system under consideration on-board g-jitters do not perturb the diffusive process.
The details on these particular results one may find in recent selected publications:
Thermo-vibrational convection. Comparison of (a) experimental from PF and ( b) numerical results. Colors show the temperature field in perpendicular directions and black dots show the trajectory of tracer particles.
Parabolic flight scenario.
Concentration field caused by vibrational convection. Results from the ISS, run 15.
Enchantment of the heat transfer by vibrations. Nusselt number as function of vibrational forcing.