Migration of DNAPL in Saturated Porous Media: Validation of High-Resolution Shock-Capturing Numerical Simulations through a Sandbox Experiment

Abstract

This paper shows a comparison between experiments carried out in a laboratory-scale sandbox where the migration of a dense nonaqueous phase liquid (DNAPL), hydrofluoroether (HFE-7100), in a saturated porous medium was investigated, and validation was performed using high-resolution shock-capturing numerical simulations to resolve the nonlinear governing coupled partial differential equations of a three-phase immiscible fluid flow. The contaminant was released using a colored fluid as a tracer for a fixed time and pressures different from the atmospheric one into the saturated zone, first by using a column laboratory experiment, and then a sandbox-scale example with a hydraulic gradient. A digital image analysis procedure was used to determine the saturation distribution of the contaminant during its migration. These results are compared with the values determined for a DNAPL migration in a similar porous media through a numerical simulation. They show good agreement with the experimental results and also show that CactusHydro can follow the migration of a plume evolution very precisely and can also be used to evaluate the effects and environmental impacts deriving from leaks of DNAPL in saturated zones.