混药器混合均匀性分析方法与在线混合变工况试验  

Mixing Uniformity Analysis Methods and In-line Mixing Experiments of Mixer under Variable Working Conditions

作　　者：代祥[1] 徐幼林[1] 宋海潮[1,2] 陈骏阳[1] 况良杰 马鲁强 DAI Xiang;XU Youlin;SONG Haichao;CHEN Junyang;KUANG Liangjie;MA Luqiang(College of Mechanical and Electronic Engineering,Nanjing Forestry University,Nanjing 210037,China;College of Mechanical Engineering,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机械工程学院,南京210023

出　　处：《农业机械学报》2018年第10期172-179,共8页Transactions of the Chinese Society for Agricultural Machinery

基　　金：江苏省基础研究计划青年基金项目(BK20170930);国家林业局948项目(2015-4-56);江苏高校"青蓝工程"项目;江苏省"333"高层次人才培养工程项目

摘　　要：直接注入式变量喷雾系统中药水混合均匀性是衡量系统性能的重要指标。为了评价混药器在线混合农药的能力,提出了混药器混合均匀性分析方法,并进行了旋动射流混合装置混合脂溶性农药的变工况(不同载流流量Q以及不同药水混合比P)在线混合试验。以基于像素的变异系数α和均匀性指数γ作为均匀性评价指标,对混药器的药水混合图像进行处理,定量分析混合均匀性。采用人工预混的方法,通过和无混药器混合图像及静置图像进行对比,验证了评价指标的准确性。变工况试验结果表明:旋动射流混药器混合脂溶性农药时,在混合比P一定的条件下,载流流量Q越大,则混合均匀性越高;不同P条件下,均在Q=2 400 mL/min(试验条件下最大载流流量)时混合均匀性达最高,Q过小,会造成混合均匀性明显下降;Q一定时,P越大,则混合均匀性越高,P较低时,需要有较高的Q才能取得良好的混合均匀性。综合分析知:2 000 mL/min≤Q≤2 400 mL/min时,可以完成不同混合比P下的药水均匀混合;800 mL/min<Q<2 000 mL/min时,可完成较高混合比P下的在线均匀混合;Q≤800 mL/min时,基本无法完成各种混合比P下的在线均匀混合。The high mixing uniformity for pesticides and carrier water was an important requirement in direct nozzle injection system(DNIS)used to alleviate the waste of pesticides and protect environment from being contaminated by pesticides residues.To evaluate the mixing effects of pesticides mixers,new analysis methods for mixing uniformity were presented and the swirling jet mixer was used to carry out the experiments of in-line mixing for the water and non-water soluble pesticides under variable working conditions.Quantitative descriptions for mixing uniformity of mixture inside the mixer were achieved based on calculating the coefficient of variation(α)and area-weighted uniformity index(γ)for the regions of interest(ROI)in the mixture images of the mixer.The accuracy of the analysis methods was verified by comparing the images of artificial premixed mixture and the images of unmixed mixture,as well as the images of mixture in standing state,and it proved that the indexes could be taken as criteria to judge whether the mixers could meet the requirements for in-line mixing or not.The experiments result under variable working conditions revealed that the mixing uniformity was increased with higher carrier flow rate and the flow rate of 2 400 mL/min gave rise to the best uniformity while the uniformity was declined heavily with lower flow rate under the conditions of settled mixing ratios.When the carrier flow rate was remained unchanged,higher mixing ratios would contribute to higher uniformity.Therefore,it was necessary to provide high flow rate to ensure good mixing uniformity when it came to lower mixing ratios.Normally,The criteria ofα=0.223 9 andγ=80.39%were set to be the thresholds for uniform mixtures and non-uniform mixtures as there were no non-scatted pesticides remaining in the mixer when the indexes were better than them.Moreover,the filtering results showed that the flow rate which was higher than 2 000 mL/min could meet the uniformity requirements at different mixing ratios while the flow rate of 800 m

关 键 词：旋动射流混药器 像素变异系数 面积加权均匀性指数 变工况 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]