间作模式下小麦联合收获机清选装置CFD-DEM气固耦合仿真与试验验证

为了提高间作模式下小麦联合收获机清选性能，研究旋风分离筒内流场和颗粒的运动状态，探索分离筒的最佳工作参数组合，运用离散元法和计算流体力学耦合的方法分析了气流与颗粒的相互作用，以喂入速度、吸杂压强、筒体高度、下椎体角度为试验因素对清选过程进行了仿真正交试验，对最佳清选参数组合完成了田间试验验证。结果表明:气流在分离筒内形成内、外旋涡，内漩涡的运动使短茎秆进入吸杂管道，籽粒在外旋涡的作用下滑落到集粮盘；仿真试验的最佳参数组合为喂入速度12 m·s^-1吸杂压强-1 800 Pa、筒体高度350 mm、下椎体的角度65°，得到的清洁率和损失率分别为92.18%和1.99%，与田间试验的误差分别为2.947%和7.428%。

The CFD-DEM gas-solid coupling simulation and experimental verification of cleaning device of wheat combine harvester for intercropping system

In order to improve the cleaning performance of wheat combine harvester for wheat/maize intercropping system, we studied the motion states of the flow field and particles in the cyclone separator and investigated the optimal working parameter combination of the separator. In this study, airflow and particle interaction was analyzed by using the coupling simulation of discrete element method and computational fluid dynamics. The factors of the cleaning process simulation orthogonal experiment used were feeding speed, the outlet pressure, the cylinder height, and the lower vertebral angle. The simulation was validated in the field. The results showed that: the inner and outer vortex was formed by the movement of airflow in the separator; the short stems were sucked into suction pipe by inner vortex movement; the seeds fell into the set plate by the effect of outside vortex. The optimal parameter combination of simulation were 12 m·s^-1 of the feeding speed, -1 800 Pa of the outlet pressure, 350 mm of the cylinder height, and 65° of the lower vertebral angle resulting in cleanliness and loss rate of 92.18% and 1.99%, respectively, and the errors were 2.947% and 7.428%, respectively compared with the field observation. Therefore, the results can provide a theoretical basis for optimizing design of small combine harvester.