An investigation of the effect of the shear rate in microalgal flocculation by implementation of population balance approach

A population balance model (PBM) has been integrated with CFD to model aggregation of microalgae particles in flocculation systems. The model includes terms to describe the rate of particle-particle collisions that lead to aggregation and breakage. Shear rate is one of the most controversial factors in PBM that highly affects this rate and generally the dynamic behavior of flocculation due to its direct effect on the collision mechanism. Here our case study was to investigate variations of the shear rate and its impact on the flocculation process. The fluid model was turbulent two-phase Eulerian/Eulerian applying the k- turbulence model and the PBM consisted of 40 particle size groups. Ansys CFX 14.5 software package has been successfully applied to couple PBM-CFD numerical investigations. Results showed that increase in shear rate of the system leads to decrease in volume average floc diameter

Keywords:

flocculation , population balance modeling , shear rate