离心式高速玉米精量排种器T形槽型孔设计与试验

    Design and test of the T-shaped hole of centrifugal high-speed maize precision seed metering device

    • 摘要: 针对离心式高速玉米精量排种器双粒种子并排填充导致重播严重的问题,该研究提出利用型孔槽对称凸台结构降低玉米种子并排填充概率的方法,设计了一种T形槽型孔。通过构建充种阶段玉米种子的力学模型,并结合玉米种子的形状特征确定了T形槽型孔基本结构参数。借助EDEM离散元仿真软件,以型孔槽前端长度、型孔槽后端面倾斜角以及型孔槽底部倾斜角为因素,以合格指数、重播指数与漏播指数为评价指标,设计二次正交旋转回归组合仿真试验。仿真试验结果表明:在作业速度18 km/h条件下,型孔槽前端长度为9.31 mm,型孔槽后端面倾斜角为43.37°与型孔槽底部倾斜角为70.5°时,排种质量最优,排种合格指数、重播指数与漏播指数分别为94.03%、1.72%与4.25%。台架验证试验结果表明:作业速度为15 km/h时,T形槽型孔的合格指数最高为95.16%,在此作业速度下,排种器的重播指数为1.42%,漏播指数为3.42%,满足高速精量播种要求;作业速度在12 ~ 21 km/h内时,T形槽型孔的平均合格指数为94.77%,相较于矩形槽型孔提升了3.13个百分点,相较于蹄型槽型孔提升了1.80个百分点,T形槽型孔的平均重播指数为2.06%,相较于矩形槽型孔降低了3.41个百分点,相较于蹄型槽型孔降低了2.49个百分点。该研究可为离心式高速玉米精量排种器优化提供参考。

       

      Abstract: Agricultural production has been dominated by mechanization in recent years. High-speed precision seeding can fully meet the requirements of high-efficiency mechanized planting. There is a high demand for the stable and excellent operational performance of the precision seed metering device. In this study, a T-shaped hole was designed to update the existing centrifugal maize precision seed metering multiple seeding. The hole-shaped symmetric tab structure was also proposed to reduce the probability of maize seed side-by-side filling. A systematic analysis was made to clarify the influence of the structural parameters in a T-shaped hole on the process of sowing. The size of the maize seed was combined to determine the values of some structural parameters of a T-shaped hole. The range of the factors was selected for the subsequent orthogonal tests. Specifically, the length of the front, the rear inclination angle, and the inclination angle of the bottom inclination angle were from 8.64 to 15.36 mm, 41.64° to 48.36°, and 64.59° to 81.41°, respectively. A three-factor three-level quadratic orthogonal rotational regression test was conducted on EDEM software using the structural parameters as test factors, while the qualified, multiple and leakage indexes as evaluation indexes. ANOVA and response surface optimization were then performed on Design Expert 13 software. A combination of optimal structural parameters was achieved in the T-shaped hole: the length of the front was 9.31 mm, the rear inclination angle was 43.37°, and the inclination angle of the bottom inclination angle was 70.5°. The predicted qualified, multiple and leakage indexes were 95.44%, 0.9% and 4.48%, respectively. Three groups of simulations were carried out to verify the optimization under the same conditions. At the same time, the qualified, multiple and leakage index of seed metering device were 94.03%, 1.72% and 4.25%, respectively. There was close to the predicted value, indicating the accurate optimization of quadratic orthogonal rotary regression. A bench test was carried out to verify the reliability of the simulation and the effectiveness of T-shaped hole, in terms of reducing multiple indexes. The qualified index of the seed metering device was 94.54% when the operating speed was 18 km/h. The relative error with the simulation was 0.54%, indicating the reliability of simulation optimization. When the working speed is 12~21 km/h, the qualified index of T-shaped hole is not less than 94.36%, the multiple index is not higher than 3.26%, and the leakage index is not higher than 3.60%, and the average qualified index of T-shaped hole is 94.77%, which is improved by 3.13 percentage points compared with rectangular shaped hole, and 1.80 percentage points compared with horseshoe shaped hole; the average mutiple index of T-shaped hole was 2.06%, a decrease of 3.41 percentage points compared to rectangular shaped holes and a decrease of 2.49 percentage points compared to horseshoe shaped hole.

       

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