Regensburg 2007 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: POSTER: Micro and Nano Fluidics

CPP 19.4: Poster

Mittwoch, 28. März 2007, 16:00–18:30, Poster B

Mechanical properties of wet granular matter — •Mario Scheel, Martin Brinkmann, Stephan Herminghaus, and Ralf Seemann — MPI for Dynamics and Self-Organization

The macroscopic mechanical properties of a dry granulate change dramatically when small amounts of liquid are added. This is due to capillary bridges forming between mutually adjacent grains in the pile, which exert an attractive force by virtue of the surface tension of the liquid. The mechanical properties of a wet model granulate consisting of glass spheres with a narrow size distribution are studied. We determine the critical fluidization acceleration for vertical agitation, the tensile strength, and the yield stress of the granulate for various liquid contents. We compare the results from these different methods with each other and discuss them in the framework of structural information extracted from x-ray tomography images of granulates, i.e. the packing density and the liquid distribution. In-situ x-ray tomography experiments reveal furthermore insights into the redistribution of the liquid within a sheared granulate and the redistribution of liquid within a formerly fluidized granulate.