UNRAVELING THE IMPACT OF VESSEL GEOMETRY IN RESONANT ACOUSTIC MIXING

This study aimed to advance the understanding of ResonantAcoustic® Mixing (RAM) and its application in industrial powder processing. RAM, which consists of vertically oscillating boundaries operating at nominally 60 Hz with accelerations up to 100 g’s, is particularly effective for mixing fine powders and materials. RAM is able to complete mixing processes 10 to 100 times faster than traditional methods without the risk of cross contamination. Despite RAM’s growing potential, the underlying mechanisms of RAM are not fully understood, limiting its optimization and broader adoption. Research in this study sought to bridge existing gaps in understanding by investigating the influence of vessel geometry on powder mixing regimes and energy in RAM. The influence of vessel geometry on mixing behavior in RAM, focusing on critical parameters including fill volume, acceleration, and vessel shape were investigated. Experiments were conducted using four representative materials—alumina, microcrystalline cellulose, talc, and salt—to capture a spectrum of material properties. Material flow and energy input were investigated through high-speed video analysis and empirical data. The results revealed distinct flow regimes and critical acceleration thresholds at which material flow regime changes occurred, varying by material type. Vessel geometry significantly affected power to mix, with negatively-drafted and narrow vessels generally resulting in higher power to mix values for cohesive powders. Salt, a free-flowing powder, exhibited more stable energy transfer dynamics with little sensitivity to vessel design. The findings provide insights into the relationships between material properties, vessel design, and operational parameters, contributing to a better understanding of RAM behavior.