Using Computational Fluid Dynamics Software to Estimate Circulation Time Distributions in Bioreactors

摘要

Nonideal mixing in many fermentation processes can lead to concentration gtradients in nutrients,oxygen,and pH,among others.These tgradients are likely to influence cellular gehavior,growth,or yield of the fermental determine whether computational fluid dynamics(CFD) goal in this study was to determine whether computational fluid dynamics(CFD) software (FLUENT 4 and MixSim) could be used to characterize the CTD in a single-impeller mixing tank.To accomplish this,CFD software was used to simulate flow fields in three different mixing tanks by meshing the tanks with a grid of elements and solving the Navier-Stokes equations using the kappa-epsilon turbulence model.Tracer particles were released for 30 s,and the time taken for these tracer particles to return to the refrerence zone was calculated.CTDs determined by experimental measurement with CTDs determined using CFD simulation.Reproducing the sitgnal processing procedures used in each of the experiments,CFD simulations captured the characteristic featurea of the expermentally measured CTDs.The CFD data suggest new signal processing procedures that predict unimodal CTDs for all three tanks.