Numerical investigation on mixing characteristics of S-shaped biomass particles in a rotary drum

As a significant renewable energy, the efficient development and utilization of biomass has attracted widespread attention. The S-shaped biomass particle is one of the special non-spherical biomass materials, which generally contain high moisture have low calorific value of combustion. Therefore, the motion behaviours and mixing performance of S-shaped biomass particles in a rotary drum are crucial during the pretreatment drying processes. A S-shaped biomass particle model was developed and validated, and the collision models of particle-to-particle and particle-to-solid boundary systems have been constructed by DEM (Discrete Element Method) approach. The effects of rotational speed, number of baffles, and the baffle height-to-drum radius ratio on the mixing quality of S-shaped biomass particle are taken into consider. It was found that increasing drum speed promotes particles mixing process and the highest mixing quality observed under the condition of 10 r min−1. The number of baffles is critical for particles mixing behaviours. Reducing the baffle height-to-drum radius ratio significantly improves the perturbation time of the particles, thereby enhancing the mixing process. The optimal mixing effect is observed at a height-to-diameter ratio of 0.12. These findings could provide guidance for recognise optimisation of industrial processes and facility design in biomass energy systems.