Abstract: Aiming at the problem that the movement law and force characteristics of the air suction seed metering device under the highspeed air flow field are very complex and difficult to accurately analyze and calculate, this paper carries out gassolid twophase simulation of the working process of the air suction soybean seed metering device and optimizes the parameters of its seed tray through the coupling method of discrete element (DEM) and computational fluid dynamics (CFD). The change law of the traction force on the seeds in the process of seed filling was analyzed, and the critical points of each stage of seed filling were divided, and the evaluation indexes of seed filling performance at each stage were defined. Taking the adsorption duration and seed removal resistance as the evaluation indexes of seed filling performance, and taking the height of the seed supporting table, the angle of the seed supporting table and the thickness of the stirring rod as the experimental factors, a three factor quadratic rotation orthogonal combination test was carried out. The response surface analysis and multiobjective optimization were carried out on the test results, and the best parameter combination of the seed metering plate was determined: the height of the seed supporting table was 2.8 mm, the angle of the seed supporting table was 31.2°, and the thickness of the stirring rod was 1.4 mm. At this time, the performance indicators of seed metering device were as follows: adsorption duration 0.104 s, seed removal resistance 0.008 1 N. The optimized results were verified by bench test, and compared with the optimized seed metering tray under different operating speeds. The bench test results showed that the seed metering performance of the optimized seed metering tray was significantly improved, and its qualification index and missed seeding index were better than the original seed metering device, which met the requirements of soybean precision sowing.

Key words: soybean, air suction seedmetering device, discrete element, CFD, gassolid coupling simulation

摘要： 针对气吸式排种器在高速气流场下种子的运动规律及受力特性复杂、难以准确分析计算的问题，通过离散元（DEM）与计算流体力学（CFD）耦合的方法，对气吸式大豆排种器的工作过程进行气固两相仿真并对其种盘参数进行优化。分析充种过程中种子所受曳力的变化规律，对充种各阶段临界点进行划分，定义各阶段充种性能评价指标。以吸附持续时间和种子移出阻力作为充种性能评价指标，以托种台高度、托种台角度、搅种杆厚度为试验因素，进行三因素二次旋转正交组合试验，并对试验结果进行响应曲面分析和多目标寻优，确定最佳的排种盘参数组合：托种台高度为2.8mm、托种台角度为31.2°、搅种杆厚度为1.4mm。此时，排种器充种性能指标为：吸附持续时间0.104s，种子移出阻力0.0081N。对优化结果进行台架试验验证，与优化前的排种盘在不同作业速度下进行对比。台架试验结果表明：优化后的排种盘的排种性能有显著提升，其合格指数和漏播指数均优于原排种器，满足大豆精量播种要求。

关键词: 大豆, 气吸式排种器, 离散元, 计算流体力学, 气固耦合仿真