CFD simulation study of internal mixing and flow of a modified airlift bioreactor

Abstract When the airlift bioreactor is applied to the field of industrial fermentation, there is a common problem of low mixing and flow efficiency due to its simple structure. In order to expand the application of airlift bioreactor in the field of industrial fermentation, a new type of airlift bioreactor with three-dimensional bumps in the draft tube has been designed to enhance the mixing and flow of gas-liquid two-phase in the reactor. In order to determine the specific influence of the three-dimensional bumps on the internal flow field of the reactor, and to provide technical reference for the improvement of the structure of the airlift bioreactor, in this paper, the CFD simulation of this type of bioreactor is carried out. Based on the Euler multiphase flow, the Realizable k-ε model was used to analyze the flow field of the reactor with average gas-liquid flow linear velocity and temperature as parameters. The results show that under certain conditions, the three-dimensional bumps inside the draft tube can effectively accelerate the gas-liquid two-phase flow and better promotes the mixing of pig manure fermentation broth and air.