(86c) X-Ray Particle Tracking in Vertical Bladed Mixers

The motion of individual granular particles in bladed industrial equipment such as vertical axis mixers, filter dryers, and high shear granulators is poorly understood despite being used in multiple industries including food and pharmaceuticals. Particle motion in this equipment is subject to competing mechanisms of mixing including diffusion, convection, and slip plane mixing. Visual observation of the particle motion is restricted to free surfaces or near the walls, whereas most velocimetric techniques are unable to capture the orientation of the particles as they move through the system.

In this study, experiments were performed in a transparent acrylic cylinder fitted with two 45^o blades to simulate a vertical axis bladed mixer. Tagged particles were introduced at different radial and axial locations in the cylinder. X-ray particle tracking was employed to obtain the trajectory, orientation, and velocity profile of the tagged particles. Tracking more than one point on the tagged particles allowed for the measurement of particle orientation as they moved through the mixer. This X-ray imaging technique will be used in the future to obtain unique data to validate computational models describing granular mixing.