Nozzle Spray Pattern Research Articles

Design and evaluation of the target spray platform

The target-oriented spraying is an effective way to minimize chemical input in agricultural production and it is important to actualizing sustainable agriculture. This article focused on the design and optimization of the target spray platform. The spray platform consists of three parts: the vision system, the spray system, and the moving platform. All components were effectively connected and preliminarily evaluated especially regarding the response time and target spray accuracy. A simulation system was built considering the real crop geometric shape and nozzle spray pattern using the Monte Carlo method. The spray simulator was used to optimize the spray height objective function of spray deposition rate and coefficient of variance for the spray deposition. The spray process can be easily visualized and compared for different spray parameters. The indoor experiment setup was built to test and optimize the parameters of the overall system, which is flexible to verify the system. Afterward, the outdoor tractor-based equipment was designed to test the system for the field environment. The experimental result showed that 80% of the crop had a spray deviation from 0 mm to 28 mm and the proposed spraying system can reduce 46.8% usage of the chemical compared to the uniform spray method.

Evaluation of Horizontal Patternators According to International Standard Requirements for Boom Sprayers

HighlightsHorizontal distribution according ISO Standard 16119 is a measurement procedure to evaluate boom sprayers.ISO Standards 5682-1 and 5682-2 establish technical requirements for horizontal patternators.In this study, three types of patternators were evaluated to test their capability to meet the standards.The evaluated patternators showed similar results for spray distribution patterns.Minor deviations from ISO Standard 5682 did not imply differences according ISO Standard 16119.Abstract. Uniformity of spray volume distribution is one of the officially established measurements for the evaluation of horizontal boom sprayers according to ISO Standard 16119 and requirements established by ISO Standard 16122. Measurement of spray distribution patterns requires the use of specific devices such as horizontal patternators, which are included in the technical specifications for ISO Standards 5682-1 and 5682-2. Three such devices were tested, including two manual patternators (fixed and mobile) and one electronic patternator. According to information provided by the manufacturers, all three patternators align with ISO requirements. This study evaluated and compared the results obtained with the three patternators. Specifically, the horizontal distributions measured by the patternators were evaluated and compared using four nozzle types (XR 11003, AIXR 11003, TTJ60 11003, and AITTJ60 11003), three boom heights, and three operating pressures. Tests were conducted to quantify single-nozzle spray patterns, the coefficient of variation (CV) of the entire boom distribution, the liquid recovery capability of the three patternators, and the ability to simulate the entire boom spray distribution from a single-nozzle spray pattern. Results demonstrated correct functioning of all three patternators, resulting in identical conclusions considering the requirements established in the ISO standards. The CV values of the horizontal distributions were less than 10% for all cases. Moreover, the trends in values for all the evaluated factors (nozzle type, boom height, and operating pressure) were the same, independent of the patternator used. Keywords: ISO 16119, ISO 16122, ISO 5682, Liquid recovery, Nozzle spray pattern, Patternator, Spray boom, Transverse distribution, Uniformity.

Experimental research on the influence of aviation fuel temperature on swirl nozzle velocity

The purpose of this research was to explore the effects of various fuel temperatures on the injection velocity of swirl nozzles. A phase Doppler particle analyzer (PDPA) and particle image velocimetry (PIV) were used to measure the velocity of fuel sprayed by an injector into the normal atmosphere. The flow characteristics and velocities of the droplet were studied at low to high temperatures (−40 °C to 80 °C). The results showed that: 1) the flow number (FN) and mass flow of the swirl nozzle decreased with the increase of the fuel temperature under the same supply pressure; 2) the existence of “pressure critical point” and “temperature critical point” makes the nozzle flow pattern and spray pattern change, thereby changing the distribution of droplet velocity and particle size in space; 3) the PDPA measurement results showed that under the same supply pressure, a larger droplet velocity on the fuel mist cone and a smaller Sauter Mean Diamter (SMD) were measured at high temperature of fuel.

Evaporative Cooling of Gas Turbine Exhaust Gas: CFD Simulation, Experimental Verification and Sensitivity Analysis

When large amount of gas turbine hot exhaust gas is required to be cooled for reuse in a closed cycle system, the conventional cooling methods will no longer be successful. The great temperature difference, the little space available for cooling, the large speed by which the exhaust gas is expelled, and finally the low exhaust gas pressure represent a great challenge for such a practice. Evaporative cooling is increasingly used as an efficient method to enhance thermal comfort in exhaust gas recirculation. In a water spray system, a cloud of very fine water droplets is produced using pressure nozzles. Analysis of spray penetration and evaporation requires a careful integration of the process conditions such as exhaust gas velocity, nozzle spray pattern, and water flow rate. The droplet size distribution is a critical input to calculations of droplet trajectory, evaporation time, and quenching rate. Computational Fluid Dynamics (CFD) is considered a valuable tool when assessing the potential and performance of evaporative cooling. In this paper, a systematic evaluation of the Lagrangian-Eulerian (LE) approach for evaporative cooling provided by the use of a water spray system with a hollow-cone configuration of two nozzles differs in rate and particle size distribution is presented. The evaluation is based on grid-sensitivity analysis and verified using experimental measurements. The effect of the hot exhaust gas temperature, the cooling water flow rate and nozzle Sauter Mean Diameter (SMD) is also presented. The results show that CFD simulation of evaporation by the LE approach, in spite of its limitations, can accurately predict the evaporation process. Finally, a good matching with the experimental measurements of the cooled exhaust gas temperature is achieved.

Dispersiveness of Liquid Droplets Sprayed with Cocurrent Gas Flow

Pneumohydraulic stand, equipped with a set of aerosol systems laser diagnostics devices, are presented. The results of experimental measurements of the aerosol liquid-drop size distribution in the ejection nozzle spray pattern are provided.

Spray Drift Reduction Technology Adjuvant Evaluation

Abstract Twelve commercial drift reduction agents were evaluated for their characteristics in the three most commonly accepted parameters for spray droplet size formation—extensional viscosity, dynamic surface tension, and kinematic viscosity. Samples were sprayed in both water and in the presence of a commercial herbicide formulation. The spray droplet spectra for these agents were then determined under rigorous control, in still-air conditions, using a Sympatec HELOS/KF laser diffraction particle size analyzer. Spraying an actual pesticide formulation that contains a wetting agent is important because the surfactant present reduces dynamic surface tension and can significantly reduce spray droplet diameter. The aerosol particle size distributions were measured using an electronic actuator that moved the nozzle spray pattern through the laser in a reproducible manner. There are multiple mechanisms that can influence both volume mean diameter and percent fines below 105 microns. There are natural and synthetic water-soluble polymers that function by increasing extensional viscosity. There are oil products that produce emulsions that keep small spray drops from forming. The droplet spectra for the different commercial products were grouped according to their specific drift reduction mechanism in order to see if a better correlation could be made on how they individually affected the resulting droplet particle size distribution.

Modelling the Dynamic Distribution of Spray Deposits

A mathematical model to estimate the spray distribution of phytopharmaceutical deposits under a spray boom is proposed. It focuses on the need to take account of the dynamic effects of the forward movement of the boom. These are related both to the horizontal and vertical boom movement and to the influence of aerodynamic factors on the nozzle spray distribution. The distribution of the spray deposits is computed by multiplying the nozzle spray pattern by the time needed to move from one position to the next. Mathematically, this is expressed by a convolution of the trajectory function with the nozzle spray pattern function. The model is validated through a dynamic test bench to reproduce the boom movements observed in the field. The chosen method to measure the distribution of the spray deposits is a chemical dosage of the sprayed potassium chloride (KCl) solution collected in Petri dishes. A pulse-width modulation (PWM) nozzle body fitted on the test bench is used to generate a dynamic distribution of spray deposits from which the dynamic two-dimensional nozzle spray pattern is reconstructed. This dynamic nozzle spray pattern introduced in the model allows a far better estimation of the spray deposit distribution to be made than the one obtained using the static nozzle spray pattern which was computed using filtered back-projection.

An Automated Computerized Spray Pattern Analysis System

Most of the patternators used currently to investigate nozzle spray pattern characteristics are of the manual type using collection cylinders. These patternators are susceptible to human error during recording and analyzing data. This process is also labor intensive and time consuming. Results of a survey conducted indicate that with manual patternators it takes an average of 34 min to collect and analyze pattern data for one nozzle.

Effect of roll angle and nozzle spray pattern on the uniformity of spray volume distribution below a boom

A computer model of the spray volume distribution below an 18 m spray boom has been used to study the effects of spray pattern from individual nozzles and boom roll angle on the uniformity of application. Results show that, for a boom set at the optimum height, the coefficient of variation increases continuously with increases in boom roll angle. This increase is shown to be a function of changes in each separate nozzle height along the boom rather than of the small changes in the angle between the central axis of the spray fan pattern and the vertical. The volume distribution from commercial flat fan nozzles is shown to be reasonably well described by a normal distribution and this distribution has been included in the simulation model to describe the volume distribution pattern below full-scale booms over a range of different roll angles.