Mixing Performance of a Bioreactor

Bioreactors have been widely used in several research and industrial areas, such as the production of ethanol, but the fluid dynamics and the mixing performance of several geometries have not been determined so far. The flow field of an industrial scale bioreactor has been predicted using a CFD commercial package. The bioreactor is 12 m tall and has a diameter of 6.5 m. There are two tangential inlets and the outlet is located at the bottom of the vessel. The lower inlet has a flow rate of 300 kg/s and the upper inlet has a flow rate of 1200 kg/s. The software used for the simulation was Ansys CFX 14.0. A non-structured mesh was used. The turbulence models used were k-ε and Reynolds stress model. In order to assess the mixing performance of the vessel, some modifications were testes, such as: the addition of baffles and the variation of the position of the inlets.