A numerical study was carried out on the motion characteristics of rapeseeds in the two-phase flow of the distribution head of an air-assisted centralised seed-metering device based on coupled simulations using computational fluid dynamics (CFD) and discrete element method (DEM). The effects of various structural and working parameters on seed motion characteristics and airflow field were investigated. The results showed that motion characteristics, collision frequency and the residence time of seeds significantly varied. Studies of the effect of structural parameters showed that an appropriate diameter to height ratio (e.g., 2.0), lid angle (e.g., 120°) and distribution head with streamlined design could effectively facilitate the movement of seeds, reduce the frequency of seed–seed and seed-wall contacts, avoid excessive residence of seeds, and improve distribution performance. With increasing airflow velocity, the movement and seed-wall collision of seeds became more intense, and the average residence time reduced. Distribution uniformity and power consumption were improved for airspeeds of 20–24 m s⁻¹ with the different rapeseed feed. The coefficient of variation of seed distribution measured in a bench test was less than 5.0%. The results will contribute to improving knowledge of the seed distribution characteristics and optimising the structure of distribution heads for the air-assisted centralised seed-metering devices.

基于计算流体动力学（CFD）和离散元法（DEM）耦合模拟，对气助式集中排种器分配头两相流油菜籽运动特性进行数值研究. 研究了各种结构和工作参数对种子运动特性和气流场的影响。结果表明，种子的运动特性、碰撞频率和停留时间差异显着。对结构参数影响的研究表明，适当的径高比（如2.0）、盖角（如120°）和流线型设计的分配头可以有效促进种子的移动，减少种子与种子的频率和种壁接触，避免种子过度滞留，并提高分销绩效。随着气流速度的增加，种子的运动和种子壁碰撞变得更加强烈，平均停留时间减少。20–24 m s 空速下的分布均匀性和功耗得到改善^-1与不同的油菜籽饲料。在台架试验中测得的种子分布变异系数小于 5.0%。研究结果将有助于提高对种子分配特性的了解，并优化空气辅助集中式种子计量装置的分配头结构。