Dresden 2003 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.83: Poster

Donnerstag, 27. März 2003, 15:30–18:00, P1

A study of liquid bridge volumes in wet granular materials. — •Mika Kohonen, Dimitrios Geromichalos, and Stephan Herminghaus — Department of Applied Physics, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany

The properties of wet granular materials are significantly influenced by the presence of liquid bridges between the constituent granules. A knowledge of the typical bridge volume as a function of the total amount of liquid present is crucial in attempting to describe the mechanical properties of wet granular materials, and is also of relevance in areas such as tertiary oil recovery and soil science. Even under equilibrium conditions the prediction of bridge volumes remains the subject of debate. Nothing, or very little, is known about bridge volumes under dynamic conditions, such as when a granular material is subject to continuous shaking. We describe measurements of equilibrium and dynamic bridge volumes in a model granular system consisting of glass spheres. The results demonstrate that the bridge volumes depend strongly on the wetting properties and viscosity of the liquid, and on the surface roughness of the granules. We also demonstrate that in polydisperse sphere samples the equilibrium volume of a liquid bridge between a given pair of spheres depends on the mean curvature of the spheres, in accordance with the notion that the equilibrium distribution of liquid must satisfy the condition of constant curvature of the liquid/vapour interface.