Brochure: horizons mission (2018)
horizons – a journey of discovery for science an society
Granular media are made up of small particles. The ESA Soft Matter Dynamics experiment (SoMaDy) will capture and describe the dynamics of granular material. As a national contribution, sample cells (CompGran) are manufactured on behalf of the DLR Space Administration for the Soft Matter Dynamics experiment. In this experiment, the dynamics of granules of various densities are examined. These dynamics are of great importance for industrial operations such as the processing of grain and plastic granules. As the granules fall to the bottom of their container very quickly on Earth, their dynamics can only be investigated under microgravity conditions.
The movement of the granules is examined using a technique known as dynamic light scattering. Here, the light scattered by individual particles is analysed to obtain information on particle size and dynamics. Of particular interest are the transitions between different states of the granules such as from a fluid-like behaviour to a solidified state. If a granular medium is liquid at first, the granules block one another when the packing density is slightly increased, hindering further movement. In ground reference measurements, the 'dynamic light scattering' analytical method will initially be developed and established in general for granular media. To this end, simulations and dynamic light scattering are used on reference systems, supplemented with X-ray imaging and X-ray tomography measurements. The results obtained will then be transferred to experiments on board the International Space Station ISS.
Besides liquids, granules are the most processed goods in terms of quantity. In-situ monitoring of industrial processes where granules occur is still difficult due to a lack of analytical procedures. These experiments should, on the one hand, unlock the behaviour of granules and facilitate its theoretical descriptions. On the other hand, measurement procedures will be developed for in-situ analysis of granular media, which is also of great interest for the monitoring of industrial processes.