Experiments and Discrete Element Simulation of the Dosing of Cohesive Powders in a Simplified Geometry

Abstract

We perform experiments and discrete element simulations on the dosing of cohesive granular materials in a simplified geometry. The setup is a simplified canister box where the powder is dosed out of the box through the action of a constant-pitch screw feeder connected to a motor. A dose consists of a rotation step followed by a period of rest before the next dosage. From the experiments, we report on the operational performance of the dosing process through a variation of dosage time, coil pitch and initial powder mass. We find that the dosed mass shows an increasing linear dependence on the dosage time and rotation speed. In contrast, the mass output from the canister is not directly proportional to an increase/decrease in the number coils. By calibrating the interparticle friction and cohesion, we show that DEM simulation can quantitatively reproduce the experimental findings for smaller masses but also overestimate arching and blockage. With appropriate homogenization tools, further insights into microstructure and macroscopic fields can be obtained. This work shows that particle scaling and the adaptation of particle properties is a viable approach to overcome the untreatable number of particles inherent in experiments with fine, cohesive powders and opens the gateway to simulating their flow in more complex geometries.