Mathematical and Experimental Studies of Dispersion in Porous Media

Stanford University, Stanford CA

Investigators

Abstract

0001441 Kitanidis The accurate quantitative evaluation of transverse dispersion is crucial in hydrogeology, environmental engineering, and other fields because of the way this process affects solute dilution and mixing of reactants. In many cases, the rate of biochemical reactions depends on the transverse dispersion coefficient. The primary objective of this research is to develop and test a new laboratory method for measuring transverse dispersion. Although there are methods for the laboratory measurement of transverse dispersion in porous media they all are based on the concept of measuring this quantity directly, which is very difficult because transverse dispersion coefficients are small. The proposed method is based on the inference of transverse dispersion from measurements of a quantity is inversely proportional to it. This work will develop and test a device for measurement of the transverse dispersion in homogeneous isotopic porous media. We will measure the Taylor dispersion coefficient in a spiral flow field. A small transverse dispersion means a large Taylor dispersion coefficient that is easy to infer with satisfactory accuracy from the breakthrough curve. The flow and transport in the device will be evaluated through experiments and mathematical modeling. Additionally, we will perform experiments with several unconsolidated porous media in order to evaluate the behavior of dispersivity with grain size and distribution, type of packing, and other variable.