Appraisal of fluid flow in a shaken bioreactor with conical bottom at different operating conditions

Abstract

The flow dynamics in cylindrical shaken bioreactors of different conical bottom geometries is investigated by means of phase-resolved particle image velocimetry. Amid the variety of shaken vessels used for bioprocess applications, a cylindrical bioreactor with a conical bottom geometry was selected to assess its potential application in three-dimensional cultures, and improve solid suspension in shaken systems. This work builds upon the study of Weheliye et al. (2013. AIChE J. 59, 344) for a flat bottom with the objective to evaluate the effects of conical shaped bottoms of different heights on the fluid flow under different operating conditions with water being the working fluid. The results provide evidence that the presence of the conical bottom affects the transition from laminar to turbulent flow documented by Weheliye et al. (2013. AIChE J. 59, 344). The conical bottom with the greatest height investigated extended significantly the range of speeds over which flow transition occurs, with high intensity vortical structures spanning over the entire height of the bioreactor at lower speeds than those reported for a flat bottom geometry. This combined with the observed higher levels of kinetic energy should provide more efficient mechanisms for solid suspension.