Fractal analysis of agricultural nozzles spray

Abstract

Fractal scaling of the exponential type is used to establish the cumulative volume (V) distribution applied through agricultural spray nozzles in size x droplets, smaller than the characteristic size X. From exponent d, we deduced the fractal dimension (D f ) which measures the degree of irregularity of the medium. This property is known as 'self-similarity'. Assuming that the droplet set from a spray nozzle is self-similar, the objectives of this study were to develop a methodology for calculating a D f factor associated with a given nozzle and to determine regression coefficients in order to predict droplet spectra factors from a nozzle, taking into account its own D f and pressure operating. Based on the iterated function system, we developed an algorithm to relate nozzle types to a particular value of D f . Four nozzles and five operating pressure droplet size characteristics were measured using a Phase Doppler Particle Analyser (PDPA). The data input consisted of droplet size spectra factors derived from these measurements. Estimated D f values showed dependence on nozzle type and independence of operating pressure. We developed an exponential model based on the D f to enable us to predict droplet size spectra factors.Significant coefficients of determination were found for the fitted model. This model could prove useful as a means of comparing the behavior of nozzles which only differ in not measurable geometric parameters and it can predict droplet spectra factors of a nozzle operating under different pressures from data measured only in extreme work pressures.

Mathematical modelling and experimental assessment of agrochemical drift using a wind tunnel

“…where the symbols A and a group some quantities in the (18) and respectively in the (19), and coincide with the symbols A and a used in (9) and (10). Now, with a negligible error on the subsequent calculation of the drift, the assumption:…”

“…where the quantities A, B, a and b are defined as in (9) and (10). By a preliminary numerical integration of ODEs (4) and (5), the result…”

Comparing Nozzles with Different Wear Rate and Working with the Same Application Rate of Different Plant Protection Products in Aspect of Plants Condition

“…One of the important factors concerning determination of the spray quality is the spray pressure which mainly affects the flow rate (capacity) of the nozzles. However, it affects the droplet size and the size distribution of these drops; usually this effect decreases the drops size, when the pressure increases (Womac, 2001;Braekman et al, 2010;Klein et al, 2011;Agüera et al, 2012). Nozzle manufactures usually define the range of the practical or feasible pressure of the spray for their nozzles to get better results of application and deposition.…”