Full
Outline
In the plot combine harvester, the impurity removal system based on the Coanda effect serves as a novel secondary cleaning device, featuring advantages of simple structure and compact spatial footprint. However, in practical applications, relying solely on the Coanda effect generated by curved surfaces can only achieve partial impurity separation, as most impurities fail to be effectively removed under airflow, resulting in suboptimal cleaning efficiency. To enhance the device's performance, strengthen the Coanda effect intensity at the end of the curved surface, and mitigate airflow diffusion, an auxiliary plate structure was introduced to the original design. Using the CFD-DEM method, the particle deflection angles of wheat grains and husk impurities were obtained for the configuration without the auxiliary plate. These angles were then utilized to determine the variation range of the auxiliary plate's free-end angle (4.89°~27.12°) through geometric relationships. Numerical simulations were employed to analyze the flow field structure within the Coanda effect zone of the device, identifying the height range (0.112~0.128 m) where abrupt velocity changes occurred at the end of the Coanda effect. Based on simulation results, the optimal length of the auxiliary plate and the positioning of its fixed end were further refined. Bench tests demonstrated that the highest cleaning efficiency was achieved when the auxiliary plate had a free-end angle of 25°, a length of 155 mm, and a fixed-end height of 0.122 m, and the impurity content in the grain is 0.998%, conclusively validating its significant role in improving device performance.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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