In the process of aeroponics cultivation,the atomizer is one of the most important influencing factors on the cultivation process.This study presented the design of an ultrasonic atomization nozzle using contact charg...In the process of aeroponics cultivation,the atomizer is one of the most important influencing factors on the cultivation process.This study presented the design of an ultrasonic atomization nozzle using contact charging and a root droplet adhesion test rig.The purpose of this study was to reveal the relationship between the main operating parameters of the high-voltage electrostatic ultrasonic atomization nozzle and the atomization effect using droplet adhesion measurements.In this study,the ultrasonic effect of nozzle was achieved by using Laval tube,and the design of the key parameters for the high-voltage electrostatic ultrasonic atomization nozzle were inlet pressure,electrostatic voltage root core electrode material and spray distance;the droplet size variation and root adhesion patterns were obtained through experiments.The best operating parameters were analyzed by using the orthogonal test method,and the droplet deposition distribution of the root system at different scales was investigated in the atomization chamber.The test results revealed that when the root core electrode material was coppe and the nozzle working parameters were at 0.4 MPa of inlet pressure,at 1.75 m the spray distance,at 12 kV of the electrostatic voltage,the root system has the highest droplet adhesion.展开更多
Droplet drift wastes pesticide,pollutes the environment,and has become one of the focus issues of agricultural crop protection.Electrostatic spray technology reduces drift to a certain degree.In order to investigate t...Droplet drift wastes pesticide,pollutes the environment,and has become one of the focus issues of agricultural crop protection.Electrostatic spray technology reduces drift to a certain degree.In order to investigate the droplet drift pattern of a conical electrostatic nozzle,the droplet drift mass center distance was defined as an experimental index and used to conduct experimental wind tunnel studies on droplet drift.A mathematical model of the droplet drift mass center distance versus electrostatic voltage and wind speed was created via the regression method.The test results showed that the electrostatic voltage had an insignificant effect on droplet drift,the wind speed and its interaction with the electrostatic voltage had significant effects on droplet drift.When the wind speed was less than 3 m/s and stable,the crop adsorbability of a droplet had a dominant effect on the droplet drift;the droplet drift decreased with the increase of electrostatic voltage.When the wind speed exceeded 3 m/s and was stable,the reduced droplet particle size had a dominant effect on droplet drift,where droplet drift increased as the electrostatic voltage increased.When the wind speed was 0 m/s and the electrostatic voltage was 12 kV,the minimum droplet drift mass center distance was 35.5 mm,which was 56 mm less than that of conventional nozzle droplet drift.Therefore,a conical electrostatic nozzle is inapplicable for operation in an environment where wind speeds exceed 3 m/s.This study provides a reference for optimizing operational parameters of conical electrostatic nozzles and improving the anti-drift capability of droplets.展开更多
为研究不同侧风和静电电压对静电喷雾雾滴飘移的影响规律,设计不同侧风(恒速风1、2、4 m/s及0~4 m/s变化的模拟自然风)及静电电压(0,2,4,6,8 k V),进行喷杆式静电喷雾机的雾滴飘移试验,测定不同静电电压下的雾滴粒径与荷质比,并对比分...为研究不同侧风和静电电压对静电喷雾雾滴飘移的影响规律,设计不同侧风(恒速风1、2、4 m/s及0~4 m/s变化的模拟自然风)及静电电压(0,2,4,6,8 k V),进行喷杆式静电喷雾机的雾滴飘移试验,测定不同静电电压下的雾滴粒径与荷质比,并对比分析雾滴飘移质量中心距和飘失率。结果表明:随着静电电压的增大,雾滴粒径减小,雾滴荷质比增大,0~8 k V电压下电极干燥和电极打湿对雾滴荷质比没有显著影响。在侧风风速为1 m/s时,0~8 k V静电喷雾的雾滴飘移中心距小于0.55 m,雾滴飘失率低于15%。在侧风风速2 m/s时,非静电喷雾的雾滴飘失率为11.9%,6~8 k V静电喷雾的雾滴飘失率超过20%,其中静电电压8 k V的雾滴飘失率(23.9%)比非静电喷雾增加100.8%。在侧风风速4 m/s时,4~8 k V静电喷雾的雾滴飘移中心距在0.9 m以上,雾滴飘失率在30%以上,其中静电电压8 k V下的雾滴飘移中心距为967.2 mm比非静电喷雾下增加了13.7%,雾滴飘失率为35.4%比非静电喷雾下增加了59.5%。相同静电电压下,2 m/s的恒速风和0~4 m/s变化的模拟自然风之间对雾滴飘失率无显著差异。该研究为优化喷雾技术参数和提高雾滴抗飘移的能力提供参考。展开更多
为了探究电极材料对静电喷嘴雾化效果和荷电性能的影响,确定设计的静电喷嘴的最佳作业参数,并明确静电作用对雾滴沉积效果的影响,以电极材料、电极电压、喷施压力和喷孔直径为喷施变量,针对设计的静电喷嘴进行室内雾化和沉积试验。研究...为了探究电极材料对静电喷嘴雾化效果和荷电性能的影响,确定设计的静电喷嘴的最佳作业参数,并明确静电作用对雾滴沉积效果的影响,以电极材料、电极电压、喷施压力和喷孔直径为喷施变量,针对设计的静电喷嘴进行室内雾化和沉积试验。研究结果表明:设计的静电喷嘴最佳电极电压为8 k V,最佳电极材料为紫铜,最佳喷施压力为170 k Pa;相比于非静电喷雾,静电作用开启后,静电喷嘴的有效喷幅增加约50 cm;在3个采样层的雾滴沉积密度依次增加了23、19、10个/cm2;在喷嘴雾化的所有雾滴中,粒径在50~120μm区间的雾滴受静电作用影响最大,静电作用开启后,此区间段内的雾滴沉积数量增加了约2倍,当雾滴粒径大于120μm时,雾滴沉积密度随雾滴粒径的增大呈下降趋势;沉积的雾滴主要是粒径在180μm以下的雾滴,因此适合最佳生物粒径为180μm及180μm以下的作物。展开更多
基金financially supported by the National Natural Science Foundation of China Program(Grant No.51975255)Jiangsu Agriculture Science and Technology Innovation Fund(Grant No.CX(18)3048)the“Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions”(Grant No.37,(2014))。
文摘In the process of aeroponics cultivation,the atomizer is one of the most important influencing factors on the cultivation process.This study presented the design of an ultrasonic atomization nozzle using contact charging and a root droplet adhesion test rig.The purpose of this study was to reveal the relationship between the main operating parameters of the high-voltage electrostatic ultrasonic atomization nozzle and the atomization effect using droplet adhesion measurements.In this study,the ultrasonic effect of nozzle was achieved by using Laval tube,and the design of the key parameters for the high-voltage electrostatic ultrasonic atomization nozzle were inlet pressure,electrostatic voltage root core electrode material and spray distance;the droplet size variation and root adhesion patterns were obtained through experiments.The best operating parameters were analyzed by using the orthogonal test method,and the droplet deposition distribution of the root system at different scales was investigated in the atomization chamber.The test results revealed that when the root core electrode material was coppe and the nozzle working parameters were at 0.4 MPa of inlet pressure,at 1.75 m the spray distance,at 12 kV of the electrostatic voltage,the root system has the highest droplet adhesion.
基金the National Key Technology R&D Program:Study and demonstration of technology and equipment for the entire cycle of large-scale production of high-quality rice(2014BAD06B01).
文摘Droplet drift wastes pesticide,pollutes the environment,and has become one of the focus issues of agricultural crop protection.Electrostatic spray technology reduces drift to a certain degree.In order to investigate the droplet drift pattern of a conical electrostatic nozzle,the droplet drift mass center distance was defined as an experimental index and used to conduct experimental wind tunnel studies on droplet drift.A mathematical model of the droplet drift mass center distance versus electrostatic voltage and wind speed was created via the regression method.The test results showed that the electrostatic voltage had an insignificant effect on droplet drift,the wind speed and its interaction with the electrostatic voltage had significant effects on droplet drift.When the wind speed was less than 3 m/s and stable,the crop adsorbability of a droplet had a dominant effect on the droplet drift;the droplet drift decreased with the increase of electrostatic voltage.When the wind speed exceeded 3 m/s and was stable,the reduced droplet particle size had a dominant effect on droplet drift,where droplet drift increased as the electrostatic voltage increased.When the wind speed was 0 m/s and the electrostatic voltage was 12 kV,the minimum droplet drift mass center distance was 35.5 mm,which was 56 mm less than that of conventional nozzle droplet drift.Therefore,a conical electrostatic nozzle is inapplicable for operation in an environment where wind speeds exceed 3 m/s.This study provides a reference for optimizing operational parameters of conical electrostatic nozzles and improving the anti-drift capability of droplets.
文摘为研究不同侧风和静电电压对静电喷雾雾滴飘移的影响规律,设计不同侧风(恒速风1、2、4 m/s及0~4 m/s变化的模拟自然风)及静电电压(0,2,4,6,8 k V),进行喷杆式静电喷雾机的雾滴飘移试验,测定不同静电电压下的雾滴粒径与荷质比,并对比分析雾滴飘移质量中心距和飘失率。结果表明:随着静电电压的增大,雾滴粒径减小,雾滴荷质比增大,0~8 k V电压下电极干燥和电极打湿对雾滴荷质比没有显著影响。在侧风风速为1 m/s时,0~8 k V静电喷雾的雾滴飘移中心距小于0.55 m,雾滴飘失率低于15%。在侧风风速2 m/s时,非静电喷雾的雾滴飘失率为11.9%,6~8 k V静电喷雾的雾滴飘失率超过20%,其中静电电压8 k V的雾滴飘失率(23.9%)比非静电喷雾增加100.8%。在侧风风速4 m/s时,4~8 k V静电喷雾的雾滴飘移中心距在0.9 m以上,雾滴飘失率在30%以上,其中静电电压8 k V下的雾滴飘移中心距为967.2 mm比非静电喷雾下增加了13.7%,雾滴飘失率为35.4%比非静电喷雾下增加了59.5%。相同静电电压下,2 m/s的恒速风和0~4 m/s变化的模拟自然风之间对雾滴飘失率无显著差异。该研究为优化喷雾技术参数和提高雾滴抗飘移的能力提供参考。
文摘为了探究电极材料对静电喷嘴雾化效果和荷电性能的影响,确定设计的静电喷嘴的最佳作业参数,并明确静电作用对雾滴沉积效果的影响,以电极材料、电极电压、喷施压力和喷孔直径为喷施变量,针对设计的静电喷嘴进行室内雾化和沉积试验。研究结果表明:设计的静电喷嘴最佳电极电压为8 k V,最佳电极材料为紫铜,最佳喷施压力为170 k Pa;相比于非静电喷雾,静电作用开启后,静电喷嘴的有效喷幅增加约50 cm;在3个采样层的雾滴沉积密度依次增加了23、19、10个/cm2;在喷嘴雾化的所有雾滴中,粒径在50~120μm区间的雾滴受静电作用影响最大,静电作用开启后,此区间段内的雾滴沉积数量增加了约2倍,当雾滴粒径大于120μm时,雾滴沉积密度随雾滴粒径的增大呈下降趋势;沉积的雾滴主要是粒径在180μm以下的雾滴,因此适合最佳生物粒径为180μm及180μm以下的作物。
文摘利用PIV技术对气液两相流场与电场耦合作用下的外混式双流体雾化器荷电喷雾流场特性进行了测量研究,设计了一种带环形气幕的荷电感应装置,以控制喷雾射流在感应荷电过程中出现的液滴卷吸.结果表明:当水流量Q由20 L·h-1增加到36 L·h-1时,射流核心区速度增大,喷雾结构逐渐呈现非对称性,随着流量的增大非对称性越明显;扇形压力pR、雾化压力pB对喷雾流场的对称性及喷雾锥角的变化起重要作用;高压静电作用使得喷雾锥角略微增大,上卷吸现象明显并出现涡旋结构,长时间工作时电极环易积液;电极环气幕压力为100 k Pa时,其低压气流可以有效弱化细小液滴的上卷吸运动,解决电极环积液问题,荷电双流体雾化器运行稳定.
