Design and Computational Fluid Dynamics Simulation of a Novel Stirred Photo-Bioreactor

Stirred photobioreactors (PBR) have been extensively used for microalgae cultivation due to their good mixing and mass transfer conditions. However, it is difficult to study the hydrodynamics behavior with experimental procedures of these PBRs. Computational Fluid Dynamics (CFD) is a common method that has been widely used to simulate the performance of PBRs, reduce the design cost and improve work efficiency. The objective of this study was to evaluate hydrodynamics and mixing conditions of a novel cactus-like PBR. A hydrodynamic study was conducted on ANSYS FLUENT. The simulation results obtained from the VOF turbulence model showed that the fluid flow exhibit similar behavior in most parts of PBR except around the impellers and the bottom of the reactor. The velocity contours showed efficient mixing performance. In addition, the turbulence kinetic energy having a vital influence on mixing characteristics was found between the values of 1.4 × 10
⁻³
and 7.5 × 10
⁻³
m
²
/s
²
and the lowest values were observed at the bottom of the reactor. Moreover, the area-weighted average of air volume fraction was calculated to be 0.0084. The obtained results could be used to re-design PBR configurations considering the sparger type and size, and the impeller placement.