摘要
针对固定翼农用飞机所搭载航空喷头施药雾滴分布研究的需要,该文依照低湍流度风洞设计原理设计了IEA-I型高速风洞。该风洞型式为直流开口式,主要由动力段、过渡段、扩散段、稳定段、收缩段及试验段等部分组成,风洞总体尺寸为9.8 m×1.2 m×1.8m（长×宽×高）;动力段选用离心风机;扩散段为小角度扩散,扩散角5°;稳定段采用六角形蜂窝器和9层阻尼网组合设计;收缩段缩比10.24;试验段截面直径为300 mm。该文采用热线风速仪,皮托管和高速PIV系统测定了风洞试验段气流品质,试验结果表明：试验段风速7.6～98 m/s连续可调,气流紊流度小于1.0%,试验段风场均匀度小于0.4%,平均气流偏角小于0.2°,气流动压稳定系数小于2.0%,归一化轴向静压梯度小于0.02。该风洞能模拟固定翼农用飞行器作业飞行条件,为进一步研究航空喷头的参数优化提供试验平台。
Agricultural aerial spray is one of the most efficient methods for large area plant protection. However, it suffers from the great loss of pesticide droplets, which is caused by the drift. Besides the impact of external environment（wind speed, flight altitude, relative humidity, and so on）, the droplet distribution scope generated by the aerial spray nozzle dominates its drift potential. The high speed wind tunnel becomes one of the most important tools for quantitatively evaluating the aerial spray nozzles, because of its repeatability and stability in providing different test conditions. The IEA-I high speed wind tunnel was designed by the authors to estimate the performance of the aerial spray nozzles mounted on the fixed-wing agricultural aircraft. In order to obtain a good flow quality, a low-turbulence wind tunnel design principle wasused to design this wind tunnel. The IEA-I high speed wind tunnel was built up at the National Engineering Research Center of Intelligent Equipment for Agriculture in Beijing in April 2015. It was an open-circuit blowing type, and composed of power section, flexible section, diffusion section, settling chamber, contraction section and test section. The total length of the wind tunnel was about 7.8 m, the height was about 2 m, and the roughness of the internal faces of the wind tunnel was less than 5 μm. A 75 k W centrifugal blower was used in the power section, which could provide a volume flow rate of 25 161m3/h at the rated fan speed of 3 000 RPM. A flexible section was used to insulate the wind tunnel body from the vibration of the power section. The diffusion section had a 5° diffusion angle to avoid flow separation. A specially designed hexagon honeycomb of stainless steel and 9 stainless steel screens with carefully selected mesh size were embedded inside the settling chamber. These kinds of structures could reconcile the flow and reduce the flow disturbances in the settling chamber. The contraction section was designed with a 5th power wall surface shape curve, a c
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2016年第6期73-81,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
植保无人机作业风场测量及雾滴飘移控制技术研究(GJHZ2015-7)
农业植保无人直升机作业技术与远程实时监控系统研发(D151100001215003)
2015年度科技创新基地培育与发展专项项目(Z151100001615016)
关键词
设计
流场
试验
风洞
航空
植保
design
flow field
experiments
wind tunnel
aerial
plant protection
