Abstract: Aiming at the problems of low utilization rate of wind energy and relatively scattered wind field in the traditional orchard airdriven sprayer, a small spray air cylinder device directly assembled with an independent fan is designed. And the internal and external flow field of the air duct device is simulated by the CFD software, the cloud image of the wind field in the inner flow field and the wind speed in the central area of the plane at different distances from the air outlet of the outer flow field are analyzed. The results show that wind velocity lines in the flow field inside the fan duct are evenly distributed, which can generate swirling wind well, and the wind energy loss is small. In the simulation model of the external flow field, the wind speed dispersion of each plane is small, the outlet wind speed reaches 17.15 m/s, which meets the outlet speed requirement of the air guide tube of the orchard sprayer.  The test platform verifies that the actual wind speed is 10.48 m/s at a distance of 0.6 m from the air outlet, compared with the simulation analysis results, the relative error is 2.58%, and the vertical spray width can reach 0.650 m, and the horizontal coverage width can reach 0.669 m, which proves that the device can cover the fruit tree canopy better under this spraying distance and provides theoretical support for the further design of the frame and the arrangement of axial flow air duct device.

Key words: fruit tree canopy, duct spray, CFD simulation, internal and external flow field, spray test

摘要： 针对传统果园风送式喷雾机存在风能利用率低、风场较为分散等问题，开发一种与独立风机直接装配的小型喷雾风筒装置。运用CFD软件对该风筒装置内外流场进行模拟仿真，分析内流场风场云图及距外流场出风口不同距离平面中心区域的风速。结果表明:风筒内流场风速线分布均匀，能很好地产生旋流风，风能损失小；在外流场中，各平面风速分散性较小，出口风速达到17.15 m/s，满足果园喷雾机的风筒出口速度要求。并通过试验平台验证在距离出风口0.6 m处，实际风速为10.48 m/s，与仿真分析结果相比，相对误差为2.58%，且竖直高度上喷幅可达0.650 m，覆盖宽度可达0.669 m，证明所设计的风筒装置在该喷雾距离下能对果树冠层有较好的覆盖性，为进一步设计机架及风筒装置布置方案提供理论支撑。

关键词: 果树冠层, 风筒喷雾, CFD模拟, 内外流场, 喷雾试验