Intelligent Engineering Systems through Artificial Neural Networks, Volume 20
50 Measurement of Solute Transport Properties Using X-Ray Computed Tomography
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X-ray computed tomography (CT) has been introduced as a method to measure fluid transport at the macropore scale to estimate transport parameters. The objective of this study was to use x-ray CT methods to measure transport of an iodide tracer in soil cores and estimate distributions of solute pore-water velocity and dispersivity. CT-measured breakthrough curve experiments were conducted for eight undisturbed soil cores removed from the surface horizon of a Sarpy loamy sand (Typic Udispamment). Breakthrough experiments with KI were conducted using an x-ray CT scanner. Based on breakthrough curves for each pixel, solute pore-water velocity and dispersivity distributions were determined. CT-measured velocity values were slightly lower (6%) than effluent-estimated values. Frequency distributions of pore-water velocity within the intact core samples were found to be normal except one which was bi-modal. CT-measured dispersivity values were 21% lower than effluent-estimated values, attributed to the additional dispersion occurring through the column end-plate. Dispersivity frequency distributions for the intact soil cores all needed transformations; one needed a 0.25 power transformation to normalize the distribution while the others needed a 0.10 power transformation. This study illustrates that the CT method is useful for evaluating solute transport on a macropore scale for porous materials.