Determination of kinematic parameters of falling drops of standard solution of pesticides during spraying, taking into account geometric dimensions variability

Abstract

Expansion of range of applied pesticides and liquid mineral fertilizers necessitates continuous improvement of spray nozzle design, allowing to create a monodisperse spray and ensure high-quality application of chemical agents at low doses and minimal losses. The issue of studying the process of falling drops with varying geometric dimensions remains sore. Studies of drop movement in air environment make it possible to determine the falling speed and coordinates on the treated surface, to substantiate the design, dimensions, optimal operating modes and parameters of sprayers and devices for protecting the spray cone from direct exposure to wind, which is especially important at the design stage of sprayer for field spraying machines. The paper presents simulation of process of falling drops of pesticide standard solution in resisting environment, considering geometric dimensions variability. An equation for drop radius variability depending on the unit motion horizontal transverse variability, formula for variability of intensity of drop decrease depending on the initial conditions and state of environment are obtained. Dependence between coefficients of drop displacement along the horizontal transverse to the unit movement axis and time is obtained, expressions for variability of drop radius depending on the horizontal displacement and the equation for variability of velocity and vertical coordinate of drop movement on time are presented. The coefficient of mass transfer from the drop surface is determined depending on the resistance coefficient, initial velocity, medium density at the border of drop and plant medium subjected to treatment. The results obtained can be used in mechanical engineering for design and testing of sprayers and nozzles, design of wind protection devices for spray cones of standard solutions of pesticides in field sprayers, in simulation of process of drop movement with varying mass.