Preliminary CFD simulation of mixing in bioreactor agitated by Rushton turbine

Abstract

Computational fluid dynamics (CFD) is a handy tool in the study of mixing problems in bioreactor dealing with ethanolic fermentation process. Due to the complexity of the bioreactor performance which involves microbial activities throughout the fermentation process, ideally mixed assumption is considered. However, in reality, the mixing mechanism of bioreactor is not perfectly mixed. In this study, the non-ideally mixed mechanism of bioreactor is described with the implementation of aeration rate and stirrer speed in the Herbert’s kinetics model. The proposed kinetics model is implemented into CFD to observe the mixing mechanism of bioreactor. CFD results show that the proposed kinetics hybrid model successfully captured the mixing mechanism of the bioreactor. In addition to that, the proposed kinetics model could predict the ethanol concentration produced throughout the fermentation process. These results show the importance of implementing non-ideally mixed behaviour in the prediction of the bioreactor performance.