Construction And Application Of The Integration Simulation Framework Of CRD Model And CFD Model Based On OpenFOAM Platform

The presence of spatial gradients such as substrate gradients or oxygen gradients in large-scale bioreactor usually have a detrimental effect on cell metabolism, causing lower yields and productivities and an increased by-product formation. Understanding the heterogeneity in industrial-scale bioreactors and its impact on cell population is very important. Methods used for bioreactor heterogeneity study can be divided into two categories: experimental methodology and simulation methodology. In this study, a model integration method based on OpenFOAM is established which can provide simulation tools for rapid development of bioprocesses.Model integration method based on Euler-Lagrange approach is established. Compared to experimental methodology, this method can provide more detailed information about the flow field. In this approach, flow field is first calculated based on commercial CFD software CFX. Initial result field is then transferred to OpenFOAM to be used to conduct the integration simulation. Finally, simulation result is passed to MATLAB and tecplot for further handling.In this study, the newly construed integration function in OpenFOAM is minly by definition and construction of MetabolicCloud class and MetabolicParcel class. Basic functions, such as substrate transport, particle movement, coupling between extra-and intra-concentrations are implemented. Problems such as flow field data transfer, calculation of surface fluxes, collision between particles and tank wall, import of turbulent data are all issued in this study. It's possible to simulate a long term fermentation process by using the proposed integration frame.Finally, a cell reaction model of Bacillus licbeniformis is integrated into the formed integration frame. When applied to a 3 L reactor, the combined model showed similar simulation result as the original model. It's proved that the combined method worked. Furthermore, batch and fed-batch results are compared to study environmental heterogeneity effects. According to fed-batch simulation in a 30 L bioreactor, a preliminary study on long-time effect of environmental heterogeneity on cell population is carried on.