Particle kinematics analysis of droplet drift in plant protection UAV spraying operation
ZOU Xiong, XU Rangshu*, LI Jingchun, LIU Zilin
Liaoning Key Laboratory of Advanced Measurement and Test Technology for Aircraft Propulsion Systems, Shenyang Aerospace University, Shenyang, Liaoning 110136, China
Abstract：In order to study the effect of droplet drift on spray quality of plant protection UAV, based on the theory of multiphase flow and the method of particle kinematics, the force and motion trajectory of droplet sprayed by plant protection UAV are theoretically analyzed and mathematically modeled. On the basis of the assumption of the velocity of wind in the ground layer and the laminar sublayer, that is, it is assumed that the velocity of the wind in the area of wind measurement is approximately a linear distribution. Then we carry out coupling iterative solution of the equation, and analyze the influence of droplet diameter, flight altitude, the magnitude and direction of the velocity of the UAV, the magnitude and direction of the velocity of the wind, the magnitude and direction of the initial velocity of the droplet to droplet drift. We further discuss the influence of the coupling action between various factors on droplet drift to get the concentration distribution of droplet drift. The results show that the magnitude and direction of the velocity of the wind have much influence on the drift distance of the droplets, and the drift distance and the initial velocity angle show a quadratic function distribution. Under the given conditions, it is calculated that the initial velocity angle is the closest to the drift distance at about 20°. The droplet drift is mainly distributed scatteredly around the nozzle.
