Imaging of water flow in porous media by magnetic resonance imaging microscopy.
Magnetic resonance imaging (MRI) was used to study the flow of water in a column 14 mm in diameter packed with glass heads. The sample was fully saturated and water was pumped through the column using a peristaltic pump, at flow rates of 125 and 250 mL h(-1). This corresponds to mean velocities of 0.5 and 1 mm s(-1), given a porosity of 0.46 m3 m(-3). Nuclear magnetic resonance (NMR) images of the proton density and velocities within a 2-mm slice were taken at a spatial resolution of 0.15 x 0.15 x 2 mm3. At a mean pore water velocity of 1 mm s(-1) we approximated hydrodynamic dispersion using NMR-measured velocity distributions in a 2-mm slice through the sample. Additionally, we conducted a step pulse tracer experiment with chloride through the same column and at identical initial and boundary conditions. We fitted the convection-dispersion equation to the breakthrough curve and compared the column scale dispersion of the tracer experiment with the respective NMR estimate derived at the slice scale.
Deurer
Markus
M
Environment and Risk Management Group, Hort Research Institute, Palmerston North, New Zealand.
Vogeler
Iris
I
Khrapitchev
Alexander
A
Scotter
Dave
D
D004784:Environmental Monitoring; D005898:Glass; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008962:Models, Theoretical; D016062:Porosity; D012987:Soil; D014872:Water Movements
D012987:Soil