Local transitions in flow phenomena through packed beds identified by MRI

Magnetic resonance imaging (MRI) velocity measurement techniques are used t o investigate flow of water and a glucose solution, of viscosity 3.89 x 10( -3) Pa.s, within the interparticle space of a cylindrical packed bed of 5 m m diameter glass ballotini. The experiments were performed over a range of Reynolds numbers from 0.84 to 14.52, spanning the regime where inertial eff ects begin to play a significant role relative to viscous forces. a transit ion from creeping to inertial flow occurs in isolated pores at a local Reyn olds number, defined for each pore within the interparticle space, of appro ximately 30. Despite this transition in flow behavior in some pores, the gr oss features of the flow pattern scale approximately with flow rate, which can be explained by considering the volume of the void space in which the f low is nearly stagnant as largely determining the pressure distribution wit hin the bed.