Authors

Abstract

Aiming at the poor seeding effect of inside-filling pneumatic high-speed precision seed-metering device for cotton, Computational Fluid Dynamics (CFD) and Discrete Element Method–Computational Fluid Dynamics (DEM-CFD) approaches were employed for simulation and optimization. The CFD technique was used to analyze the influence of key structural parameters of negative pressure air chamber on the adsorption performance of suction hole, and the DEM-CFD technique was utilized to investigate the motion law of cotton seeds inside the seed-metering device in the seed throwing link, and the optimal combination of key structural and performance parameters of the seed-metering device was obtained. Then, the simulation-optimized parameters were tested by bench test, which showed that when the suction hole diameter was 3.1 mm, forward speed was 8.4 km/h, and negative pressure was 3,178 Pa, the evaluation indexes were optimal and were 96.25% of qualification index, 1.83% of multiple sowing index, and 1.92% of missed sowing index, respectively. Further high-speed adaptability test showed that when the forward speed ranged from 6 to 12 km/h, the qualification index remained greater than 91%, and both the multiple and missed sowing index were less than 5%, meeting the agronomic requirements of high-speed precision seeding for cotton.

Abstract in Chinese

针对内充气力式棉花高速精量排种器排种效果不佳的问题，采用CFD和DEM-CFD仿真分析方法对其进行了模拟与优化。利用CFD仿真分析了负压气室关键结构参数对吸孔吸附性能的影响，采用DEM-CFD气固耦合方法探究了投种环节排种器内部棉花种子运动规律，并获得了排种器关键结构与性能参数最佳组合。仿真优化后的参数经台架排种性能试验表明，当吸孔直径为3.1 mm、前进速度为8.4 km/h、负压为3178 Pa时，其试验指标最优且为合格指数96.25%，重播指数1.83%，漏播指数1.92%。进一步经高速适应性试验表明，当前进速度为6~12 km/h时，合格指数均大于91%，重播与漏播指数均小于5%，满足棉花高速精播农艺要求。