Influencing factors research and performance experiment on droplets deposition at low wind speed

Abstract

In view of the droplet drift during aerial spraying, a droplet deposition distribution measurement system was designed to determine the droplet size under different spray pressures using LURMARK-04F80 nozzle.  Wind tunnel was used to simulate the natural wind by generating fixed-speed wind.  According to the international standard (ISO/FDIS 22856:2008), nozzle was installed at0.6m above the wind tunnel bottom.  Deposition drift was assessed by adding fluorescent tracer to the spray mixture and measuring the quantities of droplet deposition on the PE Twines which were installed perpendicular to the wind direction in a vertical and a horizontal array.  At2m distant from the static nozzle at downwind direction and0.1m above the wind tunnel bottom, five PE Twines are positioned vertically one above the other at interval of0.1m and seven PE Twines are positioned horizontally one above the other at interval of1m.  By analyzing the drift index at different positions, the influences of spray angle, nozzle angle, side wind and spray pressure on the droplet drift were studied.  Experimental results show that drift index on the line decreases as vertical and/or horizontal distance increase.  Spray pressure and wind speed have great influence on the drift parameter.  Droplets drift still exists at7m distant from the nozzle when spray pressure attains 0.4 MPa.  Wind speed attains3m/s and spray angle is 0° or wind speed attains5m/s.  Spray pressure attains 0.3 MPa and spray angle is 0°.  The drift index in the vertical and the horizontal direction when the spray angle is 0° is higher than that of the other spray angles.  When spray distance attains4m and nozzle angle attains 0°, the drift index is higher than that of the other nozzle angles.  To reduce the droplet drift when the wind speed attains5m/s, spray operation creating droplet size should be adopted and the spray angle should be adjusted.  This study provides optimized operation parameter for aerial nozzle and plays a vital role in reducing droplet drift. Keywords: wind tunnel, spray atomization, droplet deposition, drift index, nozzle, spray angle, nozzle angle DOI:  10.33440/j.ijpaa.20190201.0017 Citation: Ding S M, Xue X Y, Qin W C, Gu W, Cai C, Cui L F.  Influencing factors research and performance experiment on droplets deposition at low wind speed.  Int J Precis Agric Aviat, 2019; 2(1): 46–51.