(697c) CFD Modeling of Bioreactors: Applying Euler-Lagrange LES Technique to Investigate Effect of Pressure & Sparge Air Flow on Dissolved CO2 Profiles in a Fermentation process

To understand the inhibitory effects of CO₂ toxicity in large scale fermentations it is critical to reliably predict dissolved CO₂ levels in industry scale fermenters. In this work, we attempt to apply a Lattice Boltzmann model (LBM) based Euler-Lagrange CFD approach to simulate the time-evolution of dissolved carbon dioxide and oxygen profiles in a fermentation process. The approach presented here eliminates the manual grid meshing process and runs orders-of-magnitude faster than conventional CFD modeling tools. Since this approach conserves energy, it directly predicts energy dissipation rates and turbulent energy spectrum at arbitrary points within the domain. We utilize this approach to simulate the mixing hydrodynamics, multi-phase flow behavior and multi-scalar transport of key (dissolved oxygen and carbon dioxide) species involved in the fermentation process. Full transient simulations have been attempted. Furthermore, through the utilization of CFD, parametric variations related to changes in headspace pressure and sparge air flow have also been captured on dissolved species profiles through well designed computational experiments. The key benefits of using the Euler-Lagrange approach over a conventional Euler-Euler framework includes reduced simulation run-times, and generality of the applied physics, without a need for parameter tuning.