Optimization of airflow cylinder sieve for threshed rice separation using CFD-DEM

The airflow cylinder sieve directly affects the harvesting effect as one of the main components of the rice combine harvester. The process of grain separated from threshed rice mixture is a multi-physical random pattern. This paper constructed accurately the components particle models, and reproduced the screening process of mixture via CFD-DEM (Computational Fluid Dynamics and Discrete Element Method). Objectives of this work are to better understand the impact of airflow velocity, aperture and deflectors of cylinder sieve on separation effect of the mixture in an airflow cylinder sieve device. The optimal working parameters of sieve were developed by the OED (Orthogonal Experiment Design) and the weight of the index method. The simulations result show that airflow velocity and aperture have an impact on the loss ratio and efficiency; deflectors have implications on efficiency. It is beneficial for separation of grain from the mixture with the airflow velocity, the aperture and deflectors are of 11m/s, 11mm, and two turns, correspondingly. The experiments result carried out on the test bench with real threshed rice mixture and agree with simulations, which proved the feasibility of the results. This paper provided basic data for the design of screening unite of rice harvester's equipment.