Computational investigation of fluid dynamics in a recently developed centrifugal impeller bioreactor

Centrifugal impeller bioreactor (CIB) was recently developed for shear sensitive biological systems. To better understand its fluid velocity profile, liquid circulation flow, shear stress, and circulation time distribution (CTD), in this study a computational fluid dynamics (CFD) approach was taken to quantitatively assess the effects of major impeller designing and bioreactor operating parameters on those characteristics. Comparison of the simulated velocity profiles near the impeller tip with the experimental measurement results was carried out, and a good agreement was demonstrated. Based on the simulated circulation flow through the draft tube, a new empirical correlation of the circulation flow (QL) with respect to the impeller designing and operating parameters was established. In addition, three distinct circulation cycles were identified and their time distribution was quantified. The above information obtained from the CFD simulation and analysis is helpful to future optimization and scale-up/scale-down of the CIB.