Particle Adsorption, particle absorption and break through curves are of interest in diverse applications like automotive air filters, water filters and subsurface transport settings. They are notoriously difficult to predict because they depend on many parameters such as the adsorption capability of the material and the pore geometry of the porous media. The aim of this work is to propose ways to predict these quantities based on direct numerical simulations with the software GeoDict.
At first an accurate three-dimensional micro-structural representation of the geometry of a porous media is constructed. Examples are the CT image of a fracture in granite, and the computer model of an active carbon filter media based on a micro CT image. Based on the microstructure model the fluid flow through the pores of the media is computed. The flow field is the basis for the third step, the tracking of particles, considering their interaction with the material surfaces and modelling the timedependent absorption or adsorption on these surfaces.
For the CT image of granite the break through curves were modelled and measured for the same rock sample. On the one hand, tracer particles are monitored, and on the other hand, break through curve simulations were performed on the CT image of the same sample.
The comparison shows a good agreement between simulation and measurement. For the model of the active carbon filter media an iterative filtration simulation, with additional modelling of deposition-dependant surface-adsorption, is performed. The sub-grain porosity of the media is modelled by the effective surface adsorption on the grain surfaces.