NMR imaging was used to study dispersion in 6 mm bead pack. T1 maps were employed to measure the rate of axial spreading of paramagnetic tracers (GdCl3) inside the bead pack in the range of flow rate from 0.015 mL/s to 0.175 mL/s. From the T1 maps, tracer concentration profiles were obtained, which yielded dimensionless axial dispersion coefficient and mean transit time. Spatial variations in the dispersion coefficient were observed at flow rates above 0.08 mL/s. We hypothesized that the observed spatial oscillations in the dispersion coefficient arise from the spatial variations of the velocity distribution. To validate this mechanism we showed by simulation that similar dispersion coefficient variation occur in a layered network.
Bibliographical noteFunding Information:
Acknowledgments-This work was sponsored in part by the Army HPC Research Center under the auspices of the Department of the Army, Army Research Laboratory. The content does not necessarily reflect the position or the policy of the government, and no official endorsement should be inferred. Y.E.K. is grateful for the support of the Graduate School of the University of Minnesota in the form of Doctoral Dissertation Fellowship.
Copyright 2007 Elsevier B.V., All rights reserved.
- Bead packs
- Paramagnetic tracers