变粒径双圆盘气吸式精量排种器优化设计与试验

针对现有气吸式圆盘型精量播种机播种不同尺寸种子需要更换排种圆盘的缺陷,为节约成本、提高排种器通用性,基于现有圆盘型排种器,设计了一种变粒径双圆盘气吸式精量排种器,无需更换圆盘便可实现不同粒径种子的精量播种。阐述了排种器基本结构与工作原理,并对其工作过程及关键部件进行了理论分析,确定了型孔排布、型孔形状、型孔锥角等关键结构参数,运用Fluent仿真分析了5种组合型孔对气室流场的影响,通过仿真分析获得了最佳组合型孔参数,并在JSP-12排种试验台上进行了排种均匀性试验及正交试验,得到排种性能较好时的负压、排种盘转速等参数的合理范围。结果表明:当排种器圆盘型孔为60°锥角的倒角型型孔,转速为34. 5 r/min、负压为4. 1 k Pa时,其合格率为90. 46%、漏播率为2. 59%、重播率为6. 94%,排种性能较优,满足播种要求。通过田间试验跟踪观察种子后续生长情况,试验得出排种器的平均合格率90. 16%、漏播率2. 77%、播种各行排量一致性变异系数5. 34%、总排量稳定性变异系数4. 86%,与传统排种器相比作业质量显著提升。

Optimum Design and Test of Variable Diameter Double Disc Air Suction Precision Seeder

Aiming at the defect that the existing air-suction disc precision seeder needs to replace the seed metering disc for seeding seeds of different sizes, and in order to save cost and improve the versatility of the seed metering device, a variable-size double disc air-suction precision seeder was developed, which can realize the precision seeding of seeds of different sizes without changing the disc. Based on the existing disc-type metering device, a double disc structure with variable particle size was designed, its basic structure and working principle were expounded, theoretical analysis of the working process and key components of the metering device were made, the key structural parameters such as hole layout, hole shape and hole cone angle were determined, and Fluent simulation was used to analyze the influence of five combined holes on the flow field in the chamber. The optimum combination hole parameters were obtained by real analysis, and the uniformity test and orthogonal test of seeding were carried out on JSP-12 seeding test-bed. The reasonable ranges of negative pressure and rotational speed of seeding plate were obtained when the seeding performance was better. The results showed that the qualified rate was 90.46%, the missing rate was 2.59%, and the replaying rate was 6.94% when the disc hole of the metering device was a chamfered hole with conical angle of 60 degrees, the rotational speed was 34.5r/min and the negative pressure was 4.1kPa. The metering performance was better and the seeding requirement was satisfied. During the verification process of field experiment, the average qualified rate was 90.16%, the seeding leakage rate was 2.77%, the consistency coefficient of variation of seeding row displacement was 5.34%, and the stability coefficient of total displacement was 4.86%. Compared with traditional metering device, the operation effect was significantly improved.