基于CFD的玉米田间吊喷装置仿真设计与试验

Simulation Design and Experiment of Corn Field Spraying Device Based on CFD

为了改善玉米作物生长至中后期时中下层叶片雾滴沉积效果差,不同冠层雾滴分布不均导致植株叶片整体雾滴覆盖率低,喷施农药方式不佳造成药害和环境污染的问题,设计了一种玉米田间吊喷装置。利用数学理论几何关系结合Fluent软件确定了关键参数,即吊杆长度为1950 mm、侧下喷头距吊杆底端高度为50 mm、侧上喷头距植株顶端高度为50 mm、侧下喷头与水平方向上夹角为38.8°、侧上喷头与水平方向上夹角为43.7°。利用Design-Expert软件以吊杆侧上喷口处压强、吊杆侧下喷口处压强、机具行进速度为试验因素,以叶片平均雾滴覆盖率Y为试验指标设计三因素三水平正交试验,经方差分析后得到影响雾滴覆盖率大小因素主次顺序:行进速度>侧下压强>侧上压强。经田间试验后得到最终组合参数为机具行进速度0.8 m/s,侧上压强0.7 MPa,侧下压强0.5 MPa,雾滴覆盖率为26.54%,上、中、下层叶片雾滴覆盖率分别为28.32%、23.54%、27.75%,模型仿真与田间试验相对误差为5.05%。研究结果可为玉米植保机械的研发提供参考。

In order to solve the problems such as poor deposition effect of fog drops on the lower and middle layers of maize crops,low coverage rate of fog drops due to uneven distribution of fog drops in different canopy layers,poor pesticide spraying method and environmental pollution,a corn field spraying device was designed.The key parameters were determined by using mathematical theoretical geometric relations and Fluent software.the length of the boom was 1950 mm,the height of the side under sprinkler head from the bottom of the boom was 50 mm,the height of the side above sprinkler head from the top of the plant was 50 mm,the angle between the side under sprinkler head and the horizontal direction was 38.8°,and the angle between the side above sprinkler head and the horizontal direction was 43.7°.Using Design-Expert software,a three-factor and three-level orthogonal test was designed with the pressure at the upper nozzle of the boom side,the pressure at the lower nozzle of the boom side and the traveling speed of the machine as the test factors,and the average fog drop coverage rate of the blade Y as the test index.According to variance analysis,the primary and secondary order of factors affecting fog drop coverage is:moving speed>lateral lower pressure>lateral upper pressure.After field test,the final combination parameters are as follows:the machine speed is 0.8 m/s,the lateral upper pressure is 0.7 MPa,the lateral lower pressure is 0.5 MPa,and the fog drop coverage rate is 26.54%,The fog drop coverage rate of upper,middle and lower leaves was 28.32%,23.54% and 27.75%,respectively,and the relative error between model simulation and field test was 5.05%.The research results can provide reference for the development of corn plant protection machinery.