Design and Experiment of a Threshing and Separation System for a Comb-Type Wheat Plot Harvester Based on CFD-Dem

To address issues such as clogging of threshing units, high grain loss rates, and elevated impurity levels in wheat breeding harvesters, this study developed a combing-type threshing and separation system for wheat plot harvesters. The system adopts a closed plate-tooth threshing drum structure, where the airflow generated by the rotation of drum blades is combined with external impurity-cleaning airflow, thereby reducing material accumulation and seed retention in the threshing and separation system. CFD-DEM coupling simulations determine the optimal parameter combination: when the drum rotational speed is 891 r/min, the feeding rate is 0.58 kg/s, and the impurity-cleaning airflow speed is 22.56 m/s, the system achieves a loss rate of 0.87% and an impurity rate of 9.06%. A field performance test using this parameter combination showed that the system’s loss rate was 1.09% and impurity rate was 11.13%. This study provides a reference for the design and research of threshing and separation systems in comb-type wheat plot harvesters.