Discrete element modelling (DEM) of hemp processing using a hammermill

The discrete element method (DEM) was used to develop a model to simulate hemp processing using a hammer mill. The model was computed using a commercial software package - Particle Flow Code in Three Dimensions (PFC3D). In the model, a simulated hemp stem was defined using spherical particles connected with parallel bonds implemented in the PFC3D. The breakage of the bonds mimics the hemp breaking phenomenon within the hammermill. A micro property, bond strength of the hemp stems, was calibrated using the literature data from compression tests of hemp stems. The calibrated bond strength was 2.2 x106 Pa. With the calibrated bond strength, the model was used to simulate the power and energy distributions within the hammermill. The simulations were performed for different hammer rotational speeds and feeding masses. The results showed that both the specific kinetic and strain energies increased with the increase of the feeding mass; however, the effects of the hammer rotational speed did not follow any particular trends.