Prewetting process can reduce the contact angle between the droplet and the leaf blade,so that the droplet can more easily wet and spread,thereby increasing the quantity of deposition.To improve the effectiveness of p...Prewetting process can reduce the contact angle between the droplet and the leaf blade,so that the droplet can more easily wet and spread,thereby increasing the quantity of deposition.To improve the effectiveness of pesticides on cotton leaves,prewetting by single-rotor electric unmanned aerial vehicles(UAV)was studied,focusing on the effects of pesticide deposition on cotton leaves during the flowering period.Cotton leaves in 0°–30°,30°–60°,60°–90°leaf blade angle ranges(angle between the leaf blade and the horizontal plane)were examined.In the first experiment,four different prewetting volumes(0,1.6,3.2 and 4.8 L)were sprayed by a singlerotor electric UAV on four cotton plots(plots A–D)each with an area of 120 m^2,and then each area was sprayed with a 0.8%(w/v)ponceau 2R solution by another singlerotor electric UAV.The results revealed that with no prewetting,droplet deposition quantity decreased with increasing leaf blade inclination.After prewetting,the mean droplet deposition quantity on plots B,C and D increased by 39.8%,9.7%and 24.9%,respectively.The prewetting rate of 1.6 L per 120 m^2 had the most significant effect on improving the deposition of droplets.It was also found that the mean droplet deposition quantity in each leaf blade angle range increased after prewetting.For the leaf blade angle range 60°–90°,this increase was the most pronounced,with 0.043,0.062,0.057 and 0.048 μL·cm^(-2)in plots A–D,respectively.Also,droplet deposition uniformity in the leaf blade angle range 60°–90°was better after prewetting.These results should provide a valuable reference for future research and practice to improve the effectiveness of pesticides applied to cotton by aerial applications.展开更多
A series of air induction nozzles were tested in a high-speed wind tunnel.Droplet size spectra were measured for four air induction nozzles(IDK-120-01,IDK-120-02,IDK-120-03 and IDK-120-04)each at three spray pressures...A series of air induction nozzles were tested in a high-speed wind tunnel.Droplet size spectra were measured for four air induction nozzles(IDK-120-01,IDK-120-02,IDK-120-03 and IDK-120-04)each at three spray pressures(0.3,0.4 and 0.5 MPa)and seven different air velocities(121.7,153.4,185.5,218.4,253.5,277.5 and 305.5 km·h^(-1)).The measurement distance(0.15,0.25 and0.35 m)from the nozzle orifice was found to be important for the atomization of the droplets.The response surface method was used to analyze the experimental data.The results indicated that Dv_(0.1)and Dv_(0.5)of the droplets decreased quasi-linearly with increased wind speed,while Dv_(0.9)was affected by the quadratic of wind speed.Dv_(0.1),Dv_(0.5)and Dv_(0.9)of the droplets were all proportional to the orifice size,and were not markedly influenced by the spray pressure.The percentage of the spray volume consisting of droplets with a diameter below 100 mm(%<100 mm)was found to be quadratically related to wind speed,and was not markedly influenced by the spray pressure and orifice size.However,the effect of the orifice size on the %<200 mm could not be ignored.展开更多
基金financial support given by the National Key Technologies Research and Development Program(2016YFD0200700)
文摘Prewetting process can reduce the contact angle between the droplet and the leaf blade,so that the droplet can more easily wet and spread,thereby increasing the quantity of deposition.To improve the effectiveness of pesticides on cotton leaves,prewetting by single-rotor electric unmanned aerial vehicles(UAV)was studied,focusing on the effects of pesticide deposition on cotton leaves during the flowering period.Cotton leaves in 0°–30°,30°–60°,60°–90°leaf blade angle ranges(angle between the leaf blade and the horizontal plane)were examined.In the first experiment,four different prewetting volumes(0,1.6,3.2 and 4.8 L)were sprayed by a singlerotor electric UAV on four cotton plots(plots A–D)each with an area of 120 m^2,and then each area was sprayed with a 0.8%(w/v)ponceau 2R solution by another singlerotor electric UAV.The results revealed that with no prewetting,droplet deposition quantity decreased with increasing leaf blade inclination.After prewetting,the mean droplet deposition quantity on plots B,C and D increased by 39.8%,9.7%and 24.9%,respectively.The prewetting rate of 1.6 L per 120 m^2 had the most significant effect on improving the deposition of droplets.It was also found that the mean droplet deposition quantity in each leaf blade angle range increased after prewetting.For the leaf blade angle range 60°–90°,this increase was the most pronounced,with 0.043,0.062,0.057 and 0.048 μL·cm^(-2)in plots A–D,respectively.Also,droplet deposition uniformity in the leaf blade angle range 60°–90°was better after prewetting.These results should provide a valuable reference for future research and practice to improve the effectiveness of pesticides applied to cotton by aerial applications.
基金supported by the National Natural Science Foundation of China(31601228,31701315)the Youth Science Fund of the Beijing Natural Science Foundation(6164032)+1 种基金the Youth Science Fund of Beijing Academy of Agriculture and Forestry Sciences(QNJJ201631)Beijing Talent Program for Ruirui Zhang
文摘A series of air induction nozzles were tested in a high-speed wind tunnel.Droplet size spectra were measured for four air induction nozzles(IDK-120-01,IDK-120-02,IDK-120-03 and IDK-120-04)each at three spray pressures(0.3,0.4 and 0.5 MPa)and seven different air velocities(121.7,153.4,185.5,218.4,253.5,277.5 and 305.5 km·h^(-1)).The measurement distance(0.15,0.25 and0.35 m)from the nozzle orifice was found to be important for the atomization of the droplets.The response surface method was used to analyze the experimental data.The results indicated that Dv_(0.1)and Dv_(0.5)of the droplets decreased quasi-linearly with increased wind speed,while Dv_(0.9)was affected by the quadratic of wind speed.Dv_(0.1),Dv_(0.5)and Dv_(0.9)of the droplets were all proportional to the orifice size,and were not markedly influenced by the spray pressure.The percentage of the spray volume consisting of droplets with a diameter below 100 mm(%<100 mm)was found to be quadratically related to wind speed,and was not markedly influenced by the spray pressure and orifice size.However,the effect of the orifice size on the %<200 mm could not be ignored.
