Aj. Sederman et al., MAGNETIC-RESONANCE-IMAGING OF LIQUID FLOW AND PORE STRUCTURE WITHIN PACKED-BEDS, Chemical Engineering Science, 52(14), 1997, pp. 2239-2250
Magnetic resonance imaging (MRI) volume- and velocity-measurement tech
niques are used to probe structure-flow correlations within the interp
article space of a packed bed of ballotini. Images of the three mutual
ly orthogonal components of the velocity field are obtained in two per
pendicular slices within a bed of 5 mm diameter ballotini packed withi
n a glass column of internal diameter 4.6 cm. Comparison of flow image
s obtained for two beds of identical column-to-particle diameter ratio
but of differing length show that velocity enhancements at the walls
of the bed are greater in the shorter, more ordered, bed. A three-dime
nsional volume image of each bed is also obtained and analysed to part
ition the interparticle space into individual pores and determine the
location of pore necks. Correlations between volume flow rate and the
surface area of the constrictions (pore necks) within the interparticl
e space lie between two limiting behaviours. For pores associated with
low local Reynolds number, the volume flow rate through the constrict
ions scales as the square of the cross-sectional area of the constrict
ion, whereas at the extreme of high local Reynolds number pores show v
olume flow rates scaling with cross-sectional area. (C) 1997 Elsevier
Science Ltd. All rights reserved.