Fluidization dynamics in an impinging-jet-driven bioreactor for artificial liver system

Liquid–solid fluidized beds have been applied in the field of bioreactors for artificial liver systems. This paper uses a coupling method of computational fluid dynamics and discrete element method to numerically study the fluidization dynamics of an impinging-jet-driven bioreactor. A long tube is placed at the centerline of a cylindrical container in the bioreactor. The liquid is discharged toward the bottom of the container to form an impinging jet to drive the fluidization process of the microcapsules. The bioreactor's bed expansion height, porosity distribution, and interaction between the liquid and microcapsules are analyzed at different microcapsule densities, sizes, and flow rates. It is found that the bed expansion is proportional to the inlet flow rate and inversely proportional to the microcapsule density and size. The distribution of porosity indicates overall even fluidization, except for a dead region near the bottom periphery of the bioreactor. The dead region shrinks with increasing flow rate and expands with increasing density and size of the microcapsules. It is found that the interaction of microcapsules may play an essential role in the variations of the dead region. Understanding the fluidization dynamics of the impinging-jet-driven bioreactor is crucial in bioreactor design and optimization to improve its performance.