气吸式水稻育秧整盘播种机吸孔流场模拟与播种试验

以2BZQZ-300型水稻育秧播种机播种气室为研究对象,建立了不同孔径吸孔的局部吸种模型,运用Fluent软件对吸孔在空载工况、种子被横向和纵向吸附的负载工况时吸孔周围流场特性进行数值模拟,对其播种性均匀性进行了验证试验。结果表明:在空载和负载时,气室下部吸孔的上下负压区相对压力分布均匀,气室内吸孔之间的气流没有明显干涉;种子被横向和纵向吸附时,种子表面的气流主要集中于吸孔与种子间;随着吸孔直径增加,种子表面的有效受力面积基本呈线性增加,种子被横向吸附时有效受力区域的相对压力随孔径增加明显升高,而种子被纵向吸附时有效受力区域的相对压力变化较小,种子被横向吸附时受到的表面力明显高于纵向吸附时的表面力,有利了提高吸种率和携种稳定性。播种试验表明,播种后水稻种子在秧盘内分布均匀,总体播种均匀性系数为94.9%。

Flow Field Simulation and Seeding Experiment on Suction Nozzle of Cupule-type Rice Seeder

In order to analyze the influence of flow field distribution of cupule type rice seeder on seeding performance, a 2BZQZ-300 seeder was investigated with Fluent software. Models of different nozzle diameters were built and both horizontal and vertical seed were considered in seed suction model. Then, planting experiment was conducted to confirm seed uniformity. The results showed that, the static pressure was well distributed whether above the nozzle or below it, and there was no significant coupling effect of airflow to adjacent nozzles. And when the considered seed was picked up, most airflow appeared at the area between nozzle and seed. The effective stress area of seed surface increased linearly with the increase of nozzle diameter. The negative pressure in the effective stress areas obviously rised with the aperture increasing during horizontal suction, while there were no obvious varieties during vertical suction. Therefore, the seed surface stress in horizontal suction was significantly higher than that of vertical adsorption, which would be helpful for improving the adsorption rate and the stability of seed carrying. The pickup performance was enhanced when diameter of nozzle increased. Because of the coupling effect of seed and airflow, the surface thrust of a horizontal seed was obviously larger than a vertical one, therefore a horizontal seed was much easier to suck up and more stable to carry. As the test showed, seeds were well distributed in trays, and total uniform coefficient reached 94.9%.