农药雾滴飘移及减飘方法研究

发布时间：2018-07-04 07:06

本文选题：喷头 + 喷雾助剂　；参考：《中国农业大学》2017年博士论文

【摘要】：本文从影响雾滴飘移的因素入手,通过理论研究分析雾滴粒径、雾滴运动速度、助剂溶液特性、施药机具等因素对雾滴飘移的影响,建立雾滴飘移能量模型;继而通过PDIA以及风洞室内测试研究雾滴粒径、雾滴运动特性及飘移特性;然后针对喷杆喷雾机和植保无人机两类施药机具分别建立雾滴飘移测试系统与方法,并进行田间雾滴沉积飘移田间试验研究;最后综合室内和田间试验结果分析影响农药有效利用率的因素,确定了适用于小麦植株上的田间施药技术。主要结论如下:通过分析室内实验数据,得到以雾滴动能为自变量,雾滴飘移潜在指数DIX为因变量的数学函数,结合雾滴飘移理论和动能定律,建立雾滴飘移潜在指数与能量模型,经PDIA和风洞试验验证,可依据雾滴粒径和运动速度有效预测出雾滴飘移潜力。利用可控风洞条件研究喷雾助剂类型、浓度、密度等助剂溶液特性对雾滴飘移潜力指数DIX的影响,发现添加喷雾助剂能在一定程度上减少雾滴飘移,防飘移助剂Silwet DRS-60,Break—thru Vibrant,Greenwet 360体积浓度分别为0.8%、0.4%和0.3%时防飘效果最好;3种助剂相比,助剂SilwetDRS-60防飘效果最佳;3种助剂均应用在空心圆锥雾喷头TR80-015上时防飘效果最为显著;助剂Silwet DRS-60和Greenwet 360均对离心喷头有防飘效果,而Break-thru Vibrant对其无防飘效果;溶液密度的增加在一定程度上可以降低雾滴飘移潜力指数DIX。利用Spraytec和PDIA测试研究雾滴粒径和雾滴运动速度对雾滴飘移特性的影响,结果显示雾滴飘移量与细雾滴的体积百分比密切相关,雾滴粒径越大,VMD75μm体积百分比越小,雾滴飘移潜力越小,防飘效果越好;喷雾雾化后产生的雾滴主体部分的运动速度与雾滴粒径成正相关,增加喷雾压力能够增加雾滴的运动初速度;喷雾扇面组合应用时,喷雾扇面叠加不会对雾滴运动速度产生影响,但是能够增加雾滴粒径从而增加雾滴的运动动能,因此可以减少雾滴飘移。喷头纵向排列,喷雾扇面前后重合叠加相较于喷雾扇面交错叠加减飘效果更明显;将喷头扇面组合叠加喷雾能够减少雾滴飘移,在一定程度上解决充分利用细小雾滴与飘移之间的矛盾。通过喷杆喷雾机雾滴飘移测试系统分析室内条件下雾滴飘移情况,结果表明雾滴飘移测试系统可以遵循ISO 22369-2-2010标准,在室内测试不同喷头的雾滴飘移潜力,实时分析雾滴的飘移情况及飘移分布规律,采用飘移潜力dPV(potential drift)反映喷头的飘移特性;雾滴大小和工作压力均为影响飘移的主要因素;使用双IDK喷头组合喷雾时雾滴飘移潜力最小,该结果验证了PDIA测试结果,说明喷雾扇面组合有较好的防飘效果。喷杆喷雾机小麦田间雾滴沉积与飘移测试研究发现,双喷头组合在沉积量相同的情况下,雾滴穿透性和覆盖率不同。雾滴粒径较小时,穿透性好、易沉积、雾滴分布覆盖情况较好,但是动能小,易在运动过程中蒸发损失,因此冠层中下层沉积量较低,覆盖率较高;雾滴粒径较大时,不易飘移蒸发,但易被叶片截留、穿透性较差,大雾滴动能较大,与叶片碰撞时液滴易聚积流失或弹跳,因此不能很好的在叶片沉积分布;对于扇形雾ST系列喷头,助剂Silwet DRS-60防飘效果最好,可减少地面飘移50%,空中飘移22%,其结果与风洞测试结果一致。植保无人机雾滴飘移研究结果表明,等动量雾滴收集器rotary impactor与聚乙烯丝计算出的DIX规律相同,统计分析显示相关性较好,说明rotary impactor和聚乙烯丝收集方法均可以作为雾滴飘移的接收装置且都能很好的描述雾滴的运动及分布情况。rotary impactor在远处和高处的收集效率较高,可以作为田间试验收集飘移雾滴的有效手段。培养皿方法可以收集下风向1～20m范围内地面飘移的雾滴,能较好的体现飘移雾滴随水平距离的变化趋势与规律。雾滴飘移测试框架上的聚乙烯软管可以收集无人机周围飘移的雾滴,能较好的体现飘移雾滴随垂直距离的变化趋势与规律。植保无人机小麦田间雾滴沉积与飘移研究发现,侧风风速与rotary impactor和培养皿测得的雾滴飘移率呈极显著正相关(相关系数r分别为0.97、0.93);在影响飘移率的因素中,侧风风速的作用大于无人机飞行高度、飞行速度的因素;植保无人机在田间实际作业时要预留至少15 m以上缓冲区(安全区)以避免药液飘移产生的危害;雾滴粒径、雾滴谱、喷杆与无人机旋翼长度的比值均对雾滴飘移影响显著,尤其雾滴体积中径和粒径≤75μm的体积百分比与雾滴飘移率的相关性非常高;喷雾助剂均能在一定程度上减少雾滴飘移率。与水相比,助剂Silwet DRS-60,ASFA+B,T1602,Break-thru Vibrant,QF-LY 和 Tmax 分别减少飘移 65%,62%,59%,46%,42%,19%。助剂Silwet DRS-60可将施药缓冲区由10.1 m缩短至6.4 m。综合室内与田间试验得出,喷雾助剂的添加有助于喷杆喷雾机和植保无人机施药过程中雾滴飘移潜力的降低;喷杆喷雾机应用双喷头组合使喷雾扇面叠加,能够在一定程度上解决充分利用细小雾滴与雾滴飘移之间的矛盾,提高农药有效利用率。
[Abstract]:In this paper, from the factors affecting the droplet drift, through the theoretical study and analysis of the droplet size, the velocity of the droplet movement, the properties of the auxiliary solution, the effect of the agent and other factors on the drift of the droplets, the droplet drift energy model is established. Then the droplet diameter, the motion characteristics and the drift characteristics of the droplets are studied by PDIA and the wind tunnel test. The fog droplet drift testing system and method were established for the spray rod sprayer and the two kinds of plant protection unmanned aerial vehicles, and the field experiment of field fog droplet deposition was carried out in the field. Finally, the factors affecting the effective utilization of pesticide were analyzed in the laboratory and field test results, and the field application technology applied to the wheat plants was determined. By analyzing indoor experimental data, the potential index and energy model of droplet drift is established by using the mathematical function of the droplet kinetic energy as the independent variable, the potential index DIX of the droplet drift as the dependent variable, and the droplet drift theory and the kinetic energy law. The fog droplet size and velocity can be effectively predicted by the PDIA and wind tunnel tests. Using controlled wind tunnel conditions to study the effect of spray additives type, concentration, density and other additives on droplet drift potential index DIX, it is found that adding spray additives can reduce the drift of droplets to a certain extent, Silwet DRS-60, Break thru Vibrant, Greenwet 360, Greenwet 360 volume concentration is 0.8%, 0.4% and 0, respectively. The anti floating effect of.3% is the best. Compared with the 3 auxiliaries, the anti floating effect of auxiliary SilwetDRS-60 is the best. The 3 auxiliaries are all applied to the hollow cone spray head TR80-015, and the effect is most remarkable; the auxiliary Silwet DRS-60 and Greenwet 360 both have the anti floating effect on the centrifugal sprinkler, and the Break-thru Vibrant has no anti floating effect on it; the increase of the density of the solution is in the same way. The effect of droplet drift potential index (DIX.) is reduced to a certain extent. The effects of droplet diameter and droplet velocity on droplet drift characteristics are studied by Spraytec and PDIA tests. The results show that the drift of droplets is closely related to the volume percentage of fine droplets. The larger the droplet size, the smaller the percentage of VMD75 mu m volume, the smaller the droplet drift potential, and the drift prevention. The better the effect is, the motion velocity of the main part of the droplet produced after spray atomization is positively related to the droplet size, and the increase of spray pressure can increase the initial velocity of the droplet movement. When the spray fan surface is applied, the spray fan surface will not affect the motion velocity of the droplet, but it can increase the droplet size and increase the movement of the droplet. As a result, the droplet drift can be reduced. The spray head is arranged vertically, the overlap and superposition of the spray fan surface are more obvious than the spray fan surface, and the spray can reduce the drift of the droplet, to a certain extent, the contradiction between the fine droplets and the drift is fully utilized. The drift test system analyses the drift of droplets under indoor conditions. The results show that the droplet drift testing system can follow the ISO 22369-2-2010 standard, test the droplet drift potential of different sprinklers in the room, analyze the drift and drift distribution of the droplets in real time, and use the drift potential dPV (potential drift) to reflect the drift characteristics of the spray head. The droplet size and working pressure are the main factors affecting the drift, and the droplet drift potential is minimal when using the double IDK nozzle combination spray. The results verify the PDIA test results, indicating that the spray fan surface combination has a better anti floating effect. In the same case, the penetration and coverage of the droplets are different. The droplet size is small, the penetration is good, the deposition is easy, the droplet distribution coverage is better, but the kinetic energy is small, and the evaporation loss is easy in the movement process. Therefore, the lower layer of the canopy is low and the coverage rate is high. When the droplet size is large, it is not easy to drift and evaporate, but easily intercepted by the blade. Poor permeability, large fog drop kinetic energy, droplets easily accumulated and leaping when colliding with blades, and therefore can not be well distributed in blade deposition; for fan-shaped fog ST series sprinklers, auxiliary Silwet DRS-60 has the best anti floating effect, which can reduce ground drift 50% and air drift 22%, and the result is consistent with the wind tunnel test results. The results of the shift study show that the rotary impactor of the equal momentum fog collector is the same as that calculated by the polyethylene wire, and the statistical analysis shows that the correlation is good. It shows that both the rotary impactor and the polyethylene wire collection methods can be used as the receiving device of the droplet drift and all can well describe the movement and distribution of the droplets in.Rotary impactor. The collection efficiency in the distant and high places is high, and it can be used as an effective means to collect drift fog droplets in field experiments. The culture dish method can collect fog droplets floating on the ground within the range of 1 ~ 20m, which can better reflect the trend and law of the drift fog drop with the horizontal distance. The floating fog droplets around the UAV can better reflect the trend and law of the drift fog drop with the vertical distance. In the field of field fog droplet deposition and drift in the unmanned aerial vehicle, it is found that the wind velocity of the side wind is significantly positively correlated with the droplet drift rate measured by rotary impactor and the culture dish (the correlation coefficient r is 0.97,0.93); In the factor of rate, the effect of side wind speed is greater than the flying height of UAV and the factor of flight speed; it is necessary to reserve at least 15 m buffer zone (safety zone) to avoid the harm caused by the drift of liquid, the ratio of droplet diameter, droplet spectrum, and the ratio of the spray rod to the unmanned aerial vehicle's rotor length affect the droplet drift. In particular, the correlation between the volume percentage of the droplet volume and the particle size less than 75 mu m is highly correlated with the droplet drift rate, and the spray aids can reduce the drift rate of droplets to a certain extent. Compared with water, the additives Silwet DRS-60, ASFA+B, T1602, Break-thru Vibrant, QF-LY and Tmax reduce the drift 65%, 62%, 59%, 46%, 42%, 19%. additive Silwet DR S-60 can shorten the buffer zone from 10.1 m to 6.4 M. in a comprehensive laboratory and field experiment. The addition of the spray assistants helps to reduce the droplet drift potential during the spraying process of the spray rod sprayer and the plant protection unmanned aerial vehicle. The spray rod sprayer applies the double nozzle combination to superimpose the spray fan surface, and can solve the full use of the fine mist to a certain extent. The contradiction between droplet drift and droplet drift can improve the effective utilization rate of pesticides.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S49

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