基于CFD‑DEM耦合的大豆玉米复合种植深松气力深施肥装置设计与试验

Design and Experiment of Subsoiling Pneumatic Deep Fertilization Device for Soybean‑Corn Intercropping Based on CFD‑DEM Coupling

摘要:

针对大豆玉米带状复合种植中耕期协同深松与深施肥农艺需求，本文设计了一种深松气力深施肥装置，通过深松铲后侧集成风送式排肥系统，实现松土与肥料深施同步作业。采用计算流体力学与离散元法（CFD?DEM）耦合仿真方法优化气肥混合腔结构，以喉管收缩深度、喉管收缩角度和变径管半锥角为影响因素，以排肥管出口气流速度与肥料颗粒速度为试验指标，建立了回归模型。优化后喉管收缩深度28.08 mm、喉管收缩角度52.1°、变径管半锥角22.3°，模型预测得出肥口气流速度为16.59 m/s、肥料颗粒速度为2.69 m/s，与仿真验证误差小于1.5%。田间试验结果表明，设计的深松气力深施肥装置能够实现肥料精准稳定深施，平均施肥量偏差4.63%，各管路排肥一致性好且未发生堵塞，深松与施肥深度均达到农艺要求，大豆与玉米行深松深度稳定性系数均高于96%，施肥深度稳定性系数均高于95%。研究结果为大豆玉米复合种植下高效精准深松施肥作业提供有效装备解决方案与理论依据。

Abstract:

Aiming at the agronomic demand for synergistic subsoiling and deep fertilization during the intertillage period in soybean?corn strip intercropping, a subsoiling pneumatic deep fertilization device was designed. By integrating a pneumatic fertilizer delivery system behind the subsoiling shovel, simultaneous soil loosening and deep fertilizer application were achieved. The computational fluid dynamics and discrete element method (CFD?DEM) coupling simulation was used to optimize the structure of air?fertilizer mixing chamber. With the throat contraction depth, throat contraction angle, and transition pipe half?cone angle as influencing factors, and the airflow velocity and fertilizer particle velocity at the fertilizer outlet as test indicators, a regression model between the test indicators and influencing factors was established. The optimized parameters were as follows: throat contraction depth of 28.08 mm, throat contraction angle of 52.1°, and transition pipe half?cone angle of 22.3°. The model predicted an outlet airflow velocity of 16.59 m/s and a fertilizer particle velocity of 2.69 m/s, with a simulation verification error of less than 1.5%. Field test results showed that the designed subsoiling pneumatic deep fertilization device could achieve precise and stable deep fertilizer application, with an average fertilization deviation of 4.63%. The fertilizer discharge consistency among all pipelines was good without clogging. Both subsoiling and fertilization depths met agronomic requirements. The stability coefficients of subsoiling depth for soybean and corn rows were above 96%, and those for fertilization depth were above 95%. The research result can provide an effective equipment solution and theoretical basis for efficient and precise subsoiling and fertilization in soybean?corn intercropping systems.