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Dense colloid transport in a bifurcating fracture
Scott C James1, Constantinos V Chrysikopoulos
1Sandia National Laboratories, Geohydrology Department, P.O. Box 5800, Albuquerque, NM 87185-0735, USA. scjames@sandia.gov
Journal of Colloid and Interface Science
|December 25, 2003
Summary
Dense colloids behave differently than neutral ones at fracture bifurcations. Gravity influences dense colloid movement, causing them to favor downgradient paths, impacting their distribution.
Area of Science:
- Geosciences
- Environmental Science
- Colloid Science
Background:
- Colloid transport in fractured rock is crucial for contaminant and resource management.
- Understanding particle behavior at bifurcations is key to predicting subsurface flow paths.
- Dense colloids present unique transport challenges due to gravitational effects.
Purpose of the Study:
- To investigate the transport of dense colloids through bifurcating fractures.
- To determine the factors controlling colloid partitioning at fracture junctions.
- To compare the behavior of dense colloids with neutrally buoyant ones.
Main Methods:
- Utilized a constant spatial step particle tracking technique.
- Simulated water-saturated, bifurcating fracture environments.
- Analyzed colloid plume constituents and their partitioning ratios.
Main Results:
- Dense colloid partitioning at bifurcations is size-dependent.
- Dense colloids preferentially migrate to downgradient fractures, overriding flow rate proportions.
- Settling, diffusion, and advection times dictate colloid behavior at bifurcations.
Conclusions:
- Gravitational effects significantly alter dense colloid transport at fracture bifurcations.
- Particle size and characteristic timescales (settling, diffusion, advection) are critical parameters controlling colloid partitioning.
- Predictive models for colloid transport must account for density-driven migration in fractured media.