前飞来流和侧风对植保无人机下洗流场影响的数值模拟研究  

Numerical simulation of the effects of incoming flow and crosswinds on airflow field of plant protection UAV

作　　者：胡聪旭 周建平[1,2,3] 刘新德 许燕 Hu Congxu;Zhou Jianping;Liu Xinde;Xu Yan(School of Mechanical Engineering,Xinjiang University,Urumqi,830047,China;Xinjiang Uygur Autonomous Region Agricultural Robot and Intelligent Equipment Engineering Research Center,Urumqi,830047,China;Yecheng Walnut Industry Research Institute of Xinjiang University,Yecheng,844900,China)

机构地区：[1]新疆大学机械工程学院,乌鲁木齐市830047 [2]新疆维吾尔自治区农牧机器人及智能装备工程研究中心,乌鲁木齐市830047 [3]新疆大学叶城核桃产业研究院,新疆叶城844900

出　　处：《中国农机化学报》2022年第5期61-70,共10页Journal of Chinese Agricultural Mechanization

基　　金：国家级大学生创新创业训练计划项目(201810755079S)。

摘　　要：研究前飞来流和侧风对单旋翼植保无人机下洗流场的影响。利用格子Boltzmann方法的自适应壁面局部涡(WALE)黏度模型数值模拟CopterWorks AF25B型单旋翼油动力植保无人直升机下洗流场。通过数值模拟不同前飞和侧风速度,研究在不同前飞来流和侧风速度对单旋翼植保无人机下洗流场的影响。结果分析表明:前飞来流方向与形成的前侧涡尾迹旋向相反进而两者流速抵消是下洗流场具有抗风性的重要原因之一。在单旋翼植保无人机前飞高度一定时,前飞速度从3 m/s增大到7 m/s,下洗流场倾斜角度增大116.67%,倾斜角度达到71°,且还会发生二次偏移。下洗流场流速呈“M”形,前飞高度一定时,随着前飞速度的增加,下洗流场的两侧峰值流速间距将缩小,峰值速度出现位置与旋翼轴心距离将增大。在侧风影响的相同前飞高度和前飞速度情况下,单旋翼植保无人机下洗流场随着侧风的增大出现不同角度的偏转,且角度与侧风速度成正比。下洗流场流动结构与无侧风时相同,都呈“U”形结构;在前飞高度和速度不变情况下,不同侧风速度时下洗流场x轴偏移量服从二阶规律。为进一步研究受下洗流场影响的雾滴基本特性奠定基础和指导喷洒作业路径规划。To study the influence of incoming flow and crosswinds on airflow field of a single rotor plant protection UAV,we used a Wall-Adapting Local Eddy(WALE) model based on lattice Boltzmann method to simulate the airflow field of Copterworks AF25 B single rotor oil-powered plant protection UAV.we set Different forward flow and crosswinds velocity and numerical simulation were set to research the effects of different incoming flow and crosswinds velocity on the airflow field of a single rotor plant protection UAV.The results show that the direction of forward incoming flow is opposite to the direction of the wake of the front vortex.When the forward flight altitude of the UAV is constant,the forward flight speed increases from 3 m/s to 7 m/s,and the inclination angle of the airflow field increases by 116.67%,reaching 71°,and secondary offset occurs.The velocity of the airflow field follows an “M” shape structure.At a certain forward flight height,the distance between the peak velocity on both sides of the airflow field narrows with the increase of the forward flight speed,while the location of the peak velocity and the distance between the rotor axis increases.At a constant forward flight height and speed,the airflow field of the single-rotor plant protection UAV deflects at different angles with the increase of crosswind,and the angle is proportional to the crosswind speed.The flow structure in the airflow field is similar to that in the absence of crosswinds,showing a “U” shaped structure.Under the same forward flight height and speed,the x-axis offset of the airflow field at different crosswinds obeys the second-order law.This study lays the foundation for further study on the basic characteristics of fog droplets by airflow field and guides the planning of spraying path operation.

关 键 词：格子BOLTZMANN方法 植保无人机 数值模拟 下洗流场 

分 类 号：S252[农业科学—农业机械化工程]