Scale-up effects on flow patterns in the high shear mixing of cohesive powders

摘要: Abstract Processing of granular material often requires mixing steps in order to blend cohesive powders, distribute viscous liquids into powder beds or create agglomerates from a wet mass. For this reason, using bladed, high-speed mixers is frequently considered good solution by many types industry. However, despite the importance such processing, flow behavior inside mixer bowl generally not totally understood. In work extensive experimentation was performed comparing lab-scale (1.9 l vessel volume) that pilot-scale (65 l with mixture some pharmaceutical excipients (e.g. lactose, cellulose). The aim propose new and more detailed method for describing complex rheology an high shear impeller torque, current consumption particle image velocimetry (PIV) analysis. Particularly, dimensionless torque number proposed profile analysis isolate contributions mass fill blade clearance at base. Impeller motor were integrated PIV obtain information about surface velocity pattern changes mixer. Mass resulted be one most critical variables, as predicted model, strongly affecting patterns. An additional regimes furthermore defined according observation bed.