(83o) Micro Particle Image Velocimetry (µ-PIV) in Porous Media Using Refractive Index Matching

For description of porous media or filtration processes, often integral methods are used where the properties of the fluid and the porous medium are combined in empirical factors like e.g. in Darcy's Law. These models are often based on averaged (integral) measurements and assumptions made about the actual local structures. For understanding the mechanisms inside the porous medium it is however necessary to study local effects and hydrodynamic conditions. In this investigation the refractive index matching method (RIM)is used to measure the velocity field inside a porous medium with micro particle image velocimetry (µ-PIV). In the presented experiments, the porous sample consists of a glass structure (borosilicate 3.3) with a polished glass sphere of d=1,3mm sintered into a glass capillary D=1,7mm. The experimental results show, that it is possible to measure the velocity field behind the sphere with the µ-PIV system at a resolution of 25 microns and thus introduce a method which allows the measurement of the local velocity distribution inside a porous medium at micro-scale experimentally.

This investigations will help to get a deeper insight into transport phenomena on micro scales within porous media to understand the mechanisms of momentum and mass transfer in filtration and adsorption processes.