A NUMERICAL STUDY OF SWIRLING FLOW AND OXYGEN TRANSPORT IN A MICRO-BIOREACTOR

Abstract

A numerical model was developed for a micro-bioreactor, of working volume around a few millilitres, in which the medium was mixed by a magnetic stirrer rod at the base. The flow pattern in the micro-bioreactor was found to resemble swirling flow with vortex breakdown. To examine the conditions for vortex breakdown, the swirling flow in an enclosed cylinder with a partially rotating bottom-wall was modeled. The cylinder-to disk ratio, up to 1.6, is found to have noticeable effect on vortex breakdown. In order to model a micro-bioreactor which has a porous scaffold, a numerical method was developed to simulate the flow conditions at a fluid-porous interface. A numerical model was developed for the flow and mass transport around and through a porous scaffold in the micro-bioreactor. The results show that the Reynolds number and the Darcy number have noticeable effects on the flow and oxygen concentration within the scaffold.