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Study on flow fields in a bioreactor with perforated blades



Flow fields of a gas–liquid fluid in a bioreactor with perforated blades were evaluated with the computational fluid dynamics and particle image velocimetry (PIV). The flow pattern of the fluid was the complex turbulence, and the fluid had preferable flow fields for fermentations. Using a rotating coordinate system and a sliding mesh method, a mesh of 24 × 16 × 80 (X × Y × Z) was selected due to its high accuracy and appropriate workload. The numerical results of the two-phase flow model agreed well with the experimental results of the PIV, such as flow field characteristics and data curves. The RNG kε model was adopted, which could precisely simulate anisotropic flow fields around higher-speed blades. Whole deviations of X-, Y- and Z-direction velocities ranged only from 5.4% to 10.5%, and continuous turbulence models could effectively simulate transfer procedures of the fluid. Because of its low cost, simplicity and easy of scale-up, the bioreactor with perforated blades and its models mechanism of fluid microelements are expected to be efficient for its industrial amplification and application in food industry. © 2012 Canadian Society for Chemical Engineering