Computational studies of airlift and stirred airlift bioreactors with non-Newtonian fluid: A comparison of hydrodynamics and gas-liquid mass transfer

In this work, the hydrodynamics and gas-liquid mass transfer in airlift and stirred airlift bioreactors with non-Newtonian fluid were investigated by computational fluid dynamics (CFD) modeling. The hydrodynamics in stirred airlift bioreactor is quite different from that of conventional airlift reactor. The gas-liquid mass transfer was comprehensively assessed using five mass transfer models, such as penetration model, slip velocity model, eddy cell model, rigid model and surface renewal stretch model. The predicted averaged quantities of gas holdup, bubble size and volumetric mass transfer coefficient were in good correspondence with the experimental data. This study highlights the need for selecting suitable mass transfer models in gas-liquid flow systems.