The effects of shear rate and solid volume fraction on the size and fractal dimension of the aggregates

• Main Authors: Ming Wei Lin, 林明煒
• Other Authors: L. D. Shiau
• Format: Others
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/14959349782046347376

碩士 === 長庚大學 === 化工與材料工程學系 === 99 === The phenomenon of particle coagulation in aqueous solutions is studied in this research. Small particles in suspension have a tendency to aggregate together. As the aggregates become large, they might break into some smaller particles due to the hydrodynamic forces. The evolution of aggregate size in suspension is determined by both aggregation and breakage. The cone-and-plate experiments are employed in this work to study the aggregation an breakage of PS particles (500 nm) and PMMA (5000 nm) particles. The effects of shear rate and solid volume fraction on the size and fractal dimension of the aggregates are investigated. The experiments show that the average equilibrium size of the aggregates decreases with increasing shear rate and increases with increasing solid volume fraction. On the other hand, the fractal dimension of the aggregates approaches 2.5~2.6at equilibrium for various shear rates and solid volume fractions.