脂溶性农药旋动射流混药器结构分析与混合均匀性试验  

Structural analysis and mixing uniformity experiments of swirling jet mixer for applying fat-soluble pesticides

作　　者：宋海潮[1,2] 徐幼林[1] 郑加强[1] 汪希伟[1] 张敏[1] Song Haichao Xu Youlin Zheng Jiaqiang Wang Xiwei Zhang Min(College of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing 210037, China Nanjing Institute of Industry Technology, Nanjing 210023, China)

机构地区：[1]南京林业大学机械电子工程学院,南京210037 [2]南京工业职业技术学院,南京210023

出　　处：《农业工程学报》2016年第23期86-92,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：江苏省农机三新工程项目(NJ2014-11);2013年度江苏高校优秀科技创新团队(苏教科﹝2013﹞10号);高校研究生科研创新计划项目(KYLX_0868);江苏省333高层次人才培养工程资助项目

摘　　要：以研究乳油、悬乳剂等脂溶性农药在线混药均匀性为目的,基于产品结构分析旋动射流混药器的混合机理,并提出提高混药器混合效率的措施:继旋器起旋、螺旋收缩管、分流器切向径流和在扩散管中增加导叶等方式提高混合液旋动效率。研究了这些措施对在线射流混药器混合效果的影响。为了提高旋转效率,减少阻力损失,继旋器内设有3个导叶,导叶高度6.5 mm,导叶包角15°;扩散管内导叶高度由0逐渐增加到6.5 mm,导叶包角15°;分流器进药采用切向进入,切向角β根据农药黏度、浓度等不同而改变;收缩管收缩度为0.095,收缩管螺距128 mm,收缩角16°。经过数值仿真,水和农药能够实现螺旋状流动,喷头处药液容积分数分布均匀性指数为0.999 5,药液分布一致。试验结果发现:旋动射流混药器出口与喷头直接连接时,农药需要药泵注药才能实现在线混合;混药器出口最大混合比为99.442 5%,旋动射流混药器能够实现脂溶性农药和水均匀混合。The on-line pesticide mixing is a process with higher productivity and safer operating conditions, which can reduce pesticide wastes and pollution. To characterize jet mixing characteristics for on-line injection of pesticides, a new mixing device based on the swirling jet mechanism was conceived and developed to improve the mixing uniformity of water and fat-soluble pesticides. The swirl jet mixer consisted of a spiral curved shrink tube, a diffuser and a spiral flow generator, and could accelerate the two-phase flow＇s spiral movement and blend the 2 kinds of liquids. In order to increase the swirling efficiency of swirling jet mixer, the spiral flow generator had 3 guide vanes（height was 6.5 mm, wrap angle was 15°）; the diffuser had also 3 guide vanes, but its height was from 0 to 6.5 mm; the pitch of the spiral curved shrink tube was 128 mm, and its converging angle was 16°. A computational fluid dynamics program（FLUENT） was used to simulate the flow field inside the swirling jet mixer to optimize its design. The boundary conditions of the water and the rapeseed oil were defined to a pressure input. The boundary condition of mixer outlet was defined to a pressure output. The total gauge pressure, the initial gauge pressure and the turbulence intensity were defined. The solid wall was supposed to be a non-slip, impervious and adiabatic boundary. The segregated and implicit modeling was identified by incompressible fluid. The steady flow and the k-？ modeling of turbulent flow were identified. The mixing uniformity was evaluated by introducing the uniformity index, and the 2 kinds of liquids were blended homogenously as the uniformity index was 1. Simulation results showed that the uniformity index was 0.999 5 across the entire cross sections inside the mixer, confirming the uniform mixture characteristics with the new mixer design. To verify the simulation results, the experiments were conducted in which the fluorescent tracers were mixed with the pesticides to enable the camera to track the mixing

关 键 词：农药 计算机仿真 试验 在线旋动射流 混药器 结构分析 脂溶性农药 混合均匀性 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] S482[自动化与计算机技术—计算机科学与技术]