Optimization And Experimental Study Of Air-assisted Boom Sprayer In Different Working Conditions

Air-assisted spraying on reducing droplets drift rate, improving the droplets penetrability and deposition is one of the most effective methods of prevention and control of plant diseases and insect pests in time. But the effect of reducing drift is affected by work environment changes and the spray parameters. The precision of spraying active control parameter, considering the field dynamic work environment, ensuring the droplets deposition effect, has not been systematically studied.In this paper, based on 3 MQ-600 air-assisted sprayer, designing and making up the sprayer prototype structure, designing the fan, motor, oil cylinder and so on and doing the calculation and selection.Previous studies of drift rate on the air-assisted spraying can not show the deposition rate at the bottom of the crop canopy and canopy. To ensure that deposition under different working conditions, this paper, leveraged by a three-dimensional multiphase flow computational fluid dynamics (CFD) model with the consideration of effect of crop foliage, wind speeds, outlet speed of air curtain, spraying flow and the height from nozzle to the crop canopy, simulates the coupling interaction of natural wind (continuous phase), crop foliage, the air curtain (continuous phase) and the droplets (discrete phase) of the air-assisted boom sprayer to study the deposition rate characteristics at the bottom of the crop canopy and on the canopy. The uniform experimental design took into the four factors with three levels being applied to arrange the simulation scheme. Final conclusion:natural wind speeds, outlet velocities of air curtain and the height from nozzle to the crop canopy are the main factors affecting the deposition rate when there is crop foliage in the computational domain. The deposition rate increases with decreasing distance when the natural wind is less than 6m/s and the height from nozzle to the crop canopy is greater than 300 mm. When natural wind is in the range of 0-6m/s, followed by outlet velocity of 18 to 22m/s, the deposition rate was gradually increased on the canopy. The deposition rate on the canopy tended to decrease, if outlet velocity increases again. However the amount of deposition of the liquid below the canopy increases with wind velocity increasing. When there is smaller spacing and stagger angle without natural wind, droplets deposition effect is best.