Nonuniqueness of hydrodynamic dispersion revealed using fast 4D synchrotron x-ray imaging.

ABSTRACT: Experimental and field studies reported a significant discrepancy between the cleanup and contamination time scales, while its cause is not yet addressed. Using high-resolution fast synchrotron x-ray computed tomography, we characterized the solute transport in a fully saturated sand packing for both contamination and cleanup processes at similar hydrodynamic conditions. The discrepancy in the time scales has been demonstrated by the nonuniqueness of hydrodynamic dispersion coefficient versus injection rate (Péclet number). Observations show that in the mixed advection-diffusion regime, the hydrodynamic dispersion coefficient of cleanup is significantly larger than that of the contamination process. This nonuniqueness has been attributed to the concentration-dependent diffusion coefficient

SUBMITTER: Chen Y 

PROVIDER: S-EPMC8694585 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature