Dispersion of paramagnetic tracers in bead packs by T1 mapping: experiments and simulations.
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.
Kutsovsky
Y E
YE
Department of Chemical Engineering and Materials Science, University of Minnesota 55455, USA.
Alvarado
V
V
Davis
H T
HT
Scriven
L E
LE
Hammer
B E
BE
D003287:Contrast Media; D005682:Gadolinium; D005898:Glass; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy
D003287:Contrast Media; D005682:Gadolinium; C038958:gadolinium chloride