Numerical study on bubble-liquid two-phase turbulent hydrodynamics in extremely narrow shape bioreactor

The main objective of this work was to determine the influence of the bubble-liquid two-phase turbulent hydrodynamics on cell culture in extremely narrow shape bioreactor. An improved second-order moment bubble-liquid turbulent model and built in-house calculation source code were developed to numerically simulate the hydrodynamics that related to cell damage. Two higher gas entrance velocities of 78.3 m/s and 104.4 m/s were employed and their effects on hydrodynamic parameters, such as bubble rising and liquid flow velocities, bubble normal and shear stresses, correlation of bubble-liquid normal stresses, turbulent kinetic energy and turbulent energy dissipation rate of bubble and liquid were investigated details. All increased with gas entrance velocities increase but failed to explain an experimental observation that higher cell death at jetting region. A new correlation definition, bubble-liquid two-phase turbulent energy production term was proposed to successfully elaborate it, as well as the effects of high gas entrance velocities. Simulation results showed turbulent energy production terms are the largest at near gas jetting regions in comparison to those of developed flow regions, which are in good agreements with experimental result. Furthermore, extremely narrow shape deteriorated the cell living environment.