Experiments and discrete element simulation of the dosing of cohesive powders in a simplified geometry

• We use experiments and DEM simulations to study the dosing of cohesive powders.
• The mass per dose shows a linear dependence on the dosage time and rotation speed.
• Quantitative agreements are obtained after scaling and calibration of properties.
• Homogenization tools provide insight into macroscopic fields during dosing.
• Mass per dose decreases beyond linearity as coil number increases.

We perform experiments and discrete element simulations on the dosing of cohesive granular materials in a simplified geometry. The setup is a canister box where the powder is dosed out through the action of a constant-pitch coil feeder connected to a motor. A dosing step consists of a rotation followed by a period of rest before the next step. From the experiments, we report on the operational performance of the dosing process through a variation of dosage time, coil pitch and initial powder filling mass. We find that the mass per dose shows an increasing linear dependence on the dosage time and rotation speed. In contrast, the mass output from the canister is inversely proportional (as expected) to an increase in the number of coils.After calibrating the interparticle friction and cohesion, we show that DEM simulations with upscaled particles can quantitatively reproduce the experimental findings for smaller masses but also overestimate arching and blockage. For some parameters, with appropriate homogenization tools, further insights into macroscopic fields can be obtained.This work shows that the calibration of (upscaled) meso-particle properties is a viable approach to overcome the untreatable number of particles inherent in experiments with fine, cohesive powders and thus opens the gateway to simulating their flow in more complex geometries.

Figure optionsDownload as PowerPoint slide