Exploring the internal dynamics of resonant acoustic mixing using positron emission particle tracking

Resonant acoustic mixing (RAM) facilitates the rapid and energy-efficient mixing of diverse powders and particulate systems. However, understanding of the dynamical origins of this mixing remains limited. In this study, we use positron emission particle tracking (PEPT) - a nuclear imaging technique facilitating the high-resolution, three-dimensional tracking of particle motion - to image, for the first time, the internal dynamics of a resonant acoustic mixer. We provide first insight into the three-dimensional flow and mixing dynamics of the system, and the variation of these dynamics with key system parameters, namely fill height and vibrational acceleration. Our results show that the mixing patterns within the system remain consistent across the majority of the parameter space explored. A clear, monotonic increase in mixing rate with increasing acceleration is observed, while the influence of fill height on mixing is more complex.