Fj. Muzzio et al., Computational and experimental investigation of flow and particle settlingin a roller bottle bioreactor, BIOTECH BIO, 63(2), 1999, pp. 185-196
It is shown that cell settling is a key factor affecting the performance of
roller bottle bioreactors. The two-dimensional cross-sectional flow at the
center of a roller bottle is simulated using a finite difference method, a
nd the settling behavior of cells is simulated using particle dynamics algo
rithms and validated experimentally using fluorescent particles. The settli
ng behavior of particles in the roller bottle flow is studied using both st
eady and time dependent rotation rates. Under steady flow conditions the fl
ow is divided into two regions: one where the particles settle to the wall
and one where the particles remain suspended indefinitely. The relative siz
e of these two regions depends on the ratio of the settling velocity to the
rotation rate of the bottle. For unsteady flows generated by periodic chan
ges of the bottle rotation direction, the settling of cells is accelerated
significantly, leading to complete deposition in just a few turns of the bo
ttle. (C) 1999 John Wiley & Sons, Inc.