出风口导流分割对轴流式果园喷雾机流场的影响  

Effect of air outlet stream diversion segmentation on flow field of axial-flow orchard sprayer

作　　者：周杰 许林云[1] 周宏平[1] 郁金[1] ZHOU Jie;XU Linyun;ZHOU Hongping;YU Jin(College of Mechanical and Electronic Engineering,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学机械电子工程学院,南京210037

出　　处：《林业工程学报》2018年第6期128-134,共7页Journal of Forestry Engineering

基　　金：国家林业局"948"项目(2015-4-56)

摘　　要：针对轴流式果园风送喷雾机,构建了风送系统试验平台,进行了内外部流场的仿真分析与试验验证。分别设定了10,15及20 cm出风口间距的单双出风口结构进行试验。仿真结果表明:在挡风板上施加导流锥后,出风口处最大风速提高了36.8%,可显著提高风机的输出效率;出风口横截面上的风速分布,由轴心沿着半径增大方向直至出风口处,风速呈现增大趋势关系,距风机中心相同半径处的风速值基本一致,沿垂直中心轴左右对称分布;出风口风速沿周向分布,最大风速发生在下止风板左右两侧,离开下止风板出风口附近,周向速度分布基本一致;基于等风量分配条件,采用引流板分割成双出风口,改善了单出风口处气流速度分布的不均匀性,尤其有效提高了风筒出口附近的风速。风机外部流场的实测值与仿真值的最大平均绝对误差不超过1.67 m/s,说明采用的仿真方法可行。间距为15 cm的双出口风机形成的内部流场出风口处风速与外部流场的平均风速及最远处的末端风速均具有良好的综合特性。研究表明采用导流锥、15 cm间距、双出口结构型式的轴流式果园风送喷雾机具有良好的综合特性。The tested platform of the air supply system for an air-assisted axial-flow orchard sprayer was established,and the simulation analysis and experimental validation of internal and external flow fields were completed.Single and double-outlet structures with an interval of 10,15 or 20 cm were designed.The simulation results indicated that,after a diversion cone was placed on the air baffle,the maximum velocity at the air outlet increased by 36.8%,and the output efficiency of the fan was significantly improved.Air could evenly flow to the air outlet at the cross section of the air outlet along the axis radius increase direction,resulting in the increase of air velocity.The air velocity was basically consistent at the same distance from the fan center,and air was symmetrically distributed at the left and right of the vertical central axis.The air from the air outlet was circumferentially distributed,and the maximum air velocity existed at the left and right of the lower air baffle.The circumferential velocity was basically consistent around the air outlet of the lower fan plate.Based on equal air distribution conditions,the drainage plate was divided into double air outlets,thus improving the unevenness of air flow velocity distribution at the single air outlet,effectively increasing the air velocity around the outlet of the air duct.The maximum average absolute error between measured values and simulated values of the external flow field of the fan should not exceed 1.67 m/s,indicating that the simulation method described in this paper was suitable.The air speed at the air outlet of the internal flow field was formed in the double-outlet fan with an interval of 15 cm.The average air velocity at the external flow field and air velocity at the utmost end presented good comprehensive characteristics.It was indicated that the air-assisted axial-flow orchard sprayer with a diversion cone,a spacing of 15 cm and double-outlet structure owned good comprehensive characteristics.

关 键 词：果园喷雾机 导流锥 内部流场 出风口 外部流场 

分 类 号：S491[农业科学—植物保护]