Spray Angle Research Articles

Non-circular pressure swirl nozzles injecting into stagnant air

As far as we are aware, all the previous studies have focused on circular injectors. Here, the effect of non-circular orifice shape on pressure swirl injector was investigated experimentally. For this purpose, three injectors; circular, square and rectangular were manufactured. The nozzles had the same cross-sectional area. Water was used as the working fluid and tests were conducted at room temperature and pressure. The Weber number varied from 484 to 1936. Flow parameters of the swirl jets were obtained by an in-house image processing code. The measured parameters were: discharge coefficient, spray angle, breakup length, lateral spread, SMD of drops and wavelength of surface waves formed on the cone. The influence of nozzle shape on all these parameters are discussed.A new breakup regime morphology for non-circular pressure swirl nozzles was defined. At lower Weber numbers, the air core was trapped inside the liquid sheet and relatively large ligaments were formed and separated from the edges (fiber breakup regime). As the Weber number was increased Rayleigh-Taylor instability produced cell-like structures near the nozzle exit. These cell-like structures eventually broke up at the thickened edges of the cells and formed Christmas tree like structures (Christmas tree regime). We found that all the measured flow parameters can best be correlated as a function of Reynolds number and Weber number based on liquid sheet thickness at nozzle exit. All these correlations were reported. Breakup length and lateral spread were heavily influenced by the breakup regime. In fiber breakup regime the breakup length and lateral spread increased with increasing Weber number. However, in Christmas tree (cellular) breakup regime, breakup length and lateral spread decreased with increasing Weber number.

Aerosol deposition and emission from a United States Pharmacopeia‐induction port when using a pressurized metered‐dose inhaler with and without a valved holding chamber

AbstractThe testing of pharmaceutical aerosols includes measuring the aerodynamic particle size distribution, which is usually performed on cascade impactors. In the next generation impactor (NGI), the aerosol dose is introduced through an induction port (IP), being separated into different aerodynamic diameter ranges by seven stages and a micro‐orifice collector. The IP plays an important role in estimating the oropharyngeal deposition fraction. While the IP retains mainly large particles, it also tends to retain particles in the respirable range. In this work, the deposition of particles in the IP of an NGI is studied, both experimentally and through computational fluid dynamic (CFD) simulations. Experimental tests are conducted both with the pressurized metered‐dose inhaler (pMDI) alone and in conjunction with a cylindrical valved holding chamber (VHC). For each case, the total mass deposition that occurs in the VHC, IP, and NGI stages is measured, as well as the mass median aerodynamic diameter of the aerosol leaving the IP. The CFD simulations show minimal variations in results regardless of the injection method due to the relatively low velocity and spray angle of the pMDI‐generated aerosol. If the flap‐valve is removed from the VHC, significant particle deposition occurs upstream or within the valve region, with downstream air recirculation contributing to small particle deposition. Based on the CFD results, a correlation is proposed to accurately predict the particle escape fraction of the IP and VHC, which allows estimation of the tannin distribution of particles collected in the NGI stages, especially those corresponding to the range of respirable particles.

Justification of range limits of root spray angle of an adaptive spraying device

BACKGROUND: Oscillations of the sprayer field boom in the transverse-vertical plane causes a decrease in the quality of the technological operation. This is especially true in relation to the operation of small-sized single-support barrow-type sprayers. One of the possible solutions to compensate the effect of transverse oscillations of the boom on the quality of spraying is the use of adaptive sprayers with a variable root angle of the spray jet, responding to the position taken by the sprayer in relation to the surface being treated. AIM: Justification of the necessary limits for changing the spray angles of an adaptive sprayer for a single-support spraying device. The novelty of the research lies in the fact that insufficient attention is paid to the implementation of technologies using means of small-scale mechanization, unlike industrial agricultural machinery. METHODS: A prototype of a single-support boom motor sprayer was used as the study object. The field experiment was carried out at the experimental area of the Oryol State Agrarian University. Data acquisition on the deviation of the sprayer from the vertical axis was carried out using a specially developed angle gauge. A spreadsheet processor in the Microsoft Excel environment was used to perform mathematical processing of the decrypted experimental data. The study of the obtained analytical dependencies was carried out in the environment of the Mathcad 14.0 mathematical calculation system. RESULTS: It has been experimentally found that the maximum deviations of the sprayer from the vertical can be up to 30° during operation. At the same time, the average amplitude of the transverse operating oscillations of the boom of a single-support barrow-type boom sprayer ranges from +11° to -18°. The amplitude of the transverse oscillations of a single-support sprayer depends on the operator’s skills and the unit motion velocity. Balancing the sprayer is important due to the moment of force caused by the weight of the one-sided field boom. A formula for calculation of the spray width of one sprayer, taking into account the geometric parameters of a single-support sprayer, as well as its inclination angle in the transverse-vertical plane, has been derived. An analytical relationship that makes it possible to calculate the required limits of the root angle of the spray jet of an adaptive sprayer, taking into account the installation distance of the sprayer relative to the vertical plane passing through the support point of the sprayer, has been obtained. The values of the root spray angles for the deflectors of adaptive sprayers, with the sprayer oscillations amplitude from -18° to +11° in the transverse-vertical plane, were found. CONCLUSIONS: The practical value of the study lies in the potential of using the formula to determine the range limits of root spray angles when designing and developing adaptive sprayers.

Experimental and numerical studies of the evaporation and combustion characteristics of large-angle impinging sprays

To achieve a large fuel injection mass per cycle, using one injector will need a large nozzle, which may lead to combustion deterioration in high power density (HPD) engines. Therefore, two-injector method was adopted and then impinging sprays by two injectors were developed to promote the air/fuel mixing and combustion performance. This study investigated the spray, evaporation, ignition and soot emission characteristics of twin injectors at different impinging angles (90°, 120°, 150°, and 180°) using various high-speed imaging techniques in a constant volume chamber. Further, CFD simulations were performed to analyze the impinging sprays under HPD condition. Innovatively, a kinetic energy loss model for impinging sprays was proposed to quantify the effect of spray impingement. The results showed that the turbulent kinetic energy increased with the impinging angle, and the kinetic energy loss at any angle could be predicted by the kinetic energy loss of 180° impinging spray. The kinetic energy loss model better characterized the spray impingement process, and then more accurately predicted the atomization quality and mixing capacity compared with spray volume. Spray impingement changed fuel and soot distributions, the peak soot mass decreased with the impinging angle, which was reduced by 36.8 %, 39.8 %, 44.4 % and 45.9 % at 90 ∼ 180° impinging sprays, respectively, comparing to the single spray. These findings recommended that using a large impinging spray angle in real HPD engines can promote spray atomization and reduce soot formation.

Experimental study on heat-transfer characteristics of spray cooling for microchannel radiators

Spray cooling is an emerging and promising thermal-management solution with a wide range of applications. However, its application in engineering vehicles remains in the formative stage. In this study, an innovative spray-cooling system for engineering vehicles was proposed. The study, using thermocouples and visualisation methods, focused on how factors such as the spray angle, height, volume flow, nozzle aperture, and arrangement impact the uniformity of the surface temperature and heat-transfer enhancement. Optimal cooling was achieved using a spray angle of 60°, height of 90 mm, and flow rate of 500 l/h. Moreover, a nozzle aperture of 1.6 mm demonstrated superior efficiency in energy use and cooling. Higher temperature differentials (90–140 °C) enhanced the heat transfer but led to a 332.81 % increase in the non-uniformity of the surface temperature. Further, the study compared the spray-cooling efficiency between alumina nanofluids and deionised water. Alumina nanofluids with a 0.7 % mass fraction achieved a maximum heat-transfer coefficient of 450.6 W/(m2·K), 15.48 % higher than that of deionised water. Moreover, based on the experimental results, an empirical formula for enhanced heat transfer using spray cooling in construction machinery was developed, providing a valuable reference for guiding engineering practice. The proposed spray-cooling method, which exhibited a two- to three-time improvement over traditional air-cooled systems, holds considerable promise in the field of engineering vehicle applications.

Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl

The spray and combustion characteristics of a gas-centered swirl coaxial (GCSC) injector used in oxidizer-rich staged combustion cycle engines were analyzed. The study focused on varying the recess ratio, presence of gas swirl, and swirl direction to improve injector performance. The impact of the recess ratio was assessed by increasing it for gas jet-type injectors with varying momentum ratios. Gas-swirl effects were studied by comparing injectors with and without swirl against a baseline of a low recess ratio gas injection. In atmospheric pressure-spray experiments, injector performance was assessed using backlight photography, cross-sectional imaging with a structured laser illumination planar imaging technique (SLIPI), and droplet analysis using ParticleMaster. Increasing the recess ratio led to reduced spray angle and droplet size, and trends of gas swirl-type injectors were similar to those of high recess ratio gas jet-type injectors. Combustion tests involved fabricating combustion chamber heads equipped with identical injectors, varying only the injector type. Oxidizer-rich combustion gas, produced by a pre-burner, and kerosene served as propellants. Combustion characteristics, including characteristic velocity, combustion efficiency, and heat flux, were evaluated. Elevated recess ratios correlated with increased characteristic velocity and reduced differences in the momentum–flux ratios of injectors. However, increasing the recess ratio yielded diminishing returns on combustion efficiency enhancement beyond a certain threshold. Gas swirling did not augment characteristic velocity but notably influenced heat flux distribution. The trends observed in spray tests were related to combustion characteristics regarding heat flux and combustion efficiency. Additionally, it was possible to estimate changes in the location and shape of the flame according to the characteristics of the injector.

The Effect of Nozzle Configuration on Adsorption-Chiller Performance

Broadly defined climate protection is a powerful incentive in the search for environmentally friendly refrigeration technologies. Adsorption chillers are considered to be one such technology; however, their main disadvantages include a low cooling capacity, a low energy efficiency ratio (EER), and cyclic operation. Thus, a great deal of effort is being put into improving adsorption-chiller performance. In this paper, the influence of the spray angle, the number of nozzles, and the water flow rate through the nozzles on adsorption-chiller performance was investigated. Adsorption-chiller performance was investigated mainly in terms of the cooling capacity (CC), the energy efficiency ratio (EER), and the specific cooling power (SCP). The results indicated that the chiller’s cooling capacity increased from about 210 W to 316 W and that the EER increased from 0.110 to 0.167 when the spray angle of the nozzles was increased from 90° to 120°. It was also reported that increasing the flow rate of water through the nozzles did not improve the average cooling capacity or the other performance parameters but resulted in more stable operation of the chiller. Additionally, using six nozzles instead of three improved the average cooling capacity and EER tenfold.

Oromucosal spray products – Viscosity impact on spray performance evaluation

In recent years, the development of oromucosal drug delivery products has garnered significant attention as an opportunity for improved drug delivery and patient acceptance. Effective oromucosal drug delivery can be achieved through the combination of formulations with spray devices to tailor the administration.According to United States and European regulatory authorities, a drug product delivered and packed in a spray device is considered a combination product. This fact compels a full characterization of both the formulation and the spray device before submission. Herein, two formulations were tested using different spray designs, and the results showed low variability in the in-use actuations between formulations. The presence of Carbopol® increased the viscosity and density, requiring more priming and force to actuate, especially for device A with an actuator extension. Overall, the delivered doses were uniform and met acceptance criteria. The spray pattern of formulation 1 assembled with device A was a uniform circular plume at 30 mm, with a spray angle of 25.1° and a droplet size distribution (D90) between 591.3 and 650.5 μm.This study expects to support scientists on upcoming developments of oromucosal spray products, reinforcing the importance of investigating its quality attributes and their impact on spray performance since the early stages of development.

Gas–liquid coaxial atomization with swirl in high-pressure environments

We present recent experimental results on the dynamics of atomization of a liquid column by a coaxial turbulent gas jet, under varying air angular momentum (swirl) conditions and densities. We compare between atomization under atmospheric conditions and in a pressurized environment where the atomizing and ambient air density is 5 times the atmospheric level. For both conditions, the parameter space includes a gas-to-liquid momentum ratio in the range of M=25−56 and swirl ratios of SR=0−1. High-speed shadowgraphy images in the spray near-field are used to quantify the spatial and temporal evolution of the liquid–gas interface. In the mid-field, Phase Doppler Interferometry, collected radially across the spray, quantify droplet size, velocity, and number density distributions. At high pressure and with increasing M, we observe a decrease in spray angle when SR=0 but a spray angle increase when SR>0.5 (critical swirl). We reconcile these observations with the crown de-wetting mechanism, first observed in X-ray shadowgraphs of the spray. Crown de-wetting depends on gas inertia relative to the liquid, which increases linearly with atomization environment pressure, leading to this switch in behavior. This mechanism also explains the modified droplet radial distribution in the mid-field, with critical transition from concave to convex-shaped trends in the mean droplet size profile. Finally, we reconstruct the full spray droplet population from radial measurements, showing that swirl not only modifies the transport of droplets in the spray cross-section, but also enhances break-up and reduces the Sauter Mean Diameter globally, for all momentum ratios and pressure conditions tested.

Performance Development of Fluidic Oscillator Nozzle for Cleaning Autonomous-Driving Sensors

Contaminated autonomous-driving sensors frequently malfunction, resulting in accidents; these sensors need regular cleaning. The autonomous-driving sensor-cleaning nozzle currently used is the windshield-washer nozzle; few studies have focused on the sensor-cleaning nozzle. We investigated the flow characteristics of the nozzle to improve its performance in cleaning the autonomous-driving sensor. The nozzle concept was based on the fluidic oscillator nozzle. Various performance parameters of the fluidic oscillator nozzle were selected and investigated. Transient fluid flow was simulated to determine the effect of the design parameters to maximize the oscillation flow phenomenon. Additionally, the spray angle and frequency were calculated. Analysis results showed that the change in flow speed affects the frequency, and the change in feedback-channel-inlet flow rate affects the angle change. To verify the simulation result, the three best models (R4+RC10, R6+RC11, R8+RC10) and the base model were manufactured and tested. The test results were consistent with the simulation results within a 6% error.

Mist-control of polyalphaolefin (PAO) lubricants using long pairwise end-associative polymers

Accidental release of pressurized hydrocarbon fuels and lubricants are a major fire hazard due to the formation of small droplet mists that can readily evaporate and ignite. Mist control through increasing droplet size and suppressing droplets has been previously demonstrated with high molecular weight polymer additives, but traditional long polymer additives do not survive the pumping that would usually precede accidental release. This constraint inspired associative polymer additives that can transiently form the high molecular weights needed for mist control, while reversibly breaking during pumping. A prior study demonstrated the efficacy of such a system in fuel: long telechelic polycyclooctadiene (PCOD) with pairwise associating acid and base end-groups. Here, we address an obstacle to applying this same polymeric system in a polyalphaolefin (PAO) solvent—its poorer solvent quality for PCOD than fuel. We measured the effects of the end-associative PCOD compared to a non-associative control on the rheological properties of solutions in both PAO (a common lubricant and heat transfer fluid) and decahydronapthalene (decalin, a solvent with PCOD solubility similar to fuel) in shear and extension, and connect those rheological modifications to observed changes in PAO spray under simulated accidental release conditions. The PCOD additives demonstrated substantial mist control in PAO, both in terms of reduced spray angle and droplet suppression. Despite the worse solubility in PAO and thus smaller effective coil size, these associative PCOD additives are effective at the low concentrations (¡0.1 wt %) necessary for practical use as a safety measure.

Influence of Spray Angle on Particle Deposition and Thermal Shock Lifetime of Embedded Micro-Agglomerated Particle Coatings

The development of gas turbine technology has led to an increase in the complexity of the geometric shape of the sprayed workpiece. Consequently, it has become more difficult to maintain the perpendicularity of the spraying angle during the spraying process, thereby impacting the structure and performance of the coating. This study uses the atmospheric plasma spraying method to simultaneously spray two types of powder for the preparation of embedded micro-agglomerated particle (EMAP) coatings. The spraying process is conducted at four different angles, ranging from 90° to 30°, in order to analyze the influence of the spray angle on the particle deposition and coating performance. The experimental results demonstrate that the relative deposition efficiency, hardness, and elastic modulus of the EMAP coatings decreased as the spray angle decreased. The porosity exhibited a reduction when the spraying angle dropped from 90° to 50°, followed by a significant rise at 30°. The greatest relative amount of second phase particles embedded in the coating appeared at a spraying angle of 90°, amounting to 10.8%. The smallest amount was found at a spraying angle of 30°, with a relative quantity of 2.2%. Furthermore, the molten droplets of the first phase matrix powder underwent extension and fragmentation along the angular direction at low angles. At an angle of 90°, the maximum average thermal shock life was 40.6 cycles, with the best stability of thermal shock life. The decrease in the spraying angle resulted in a deterioration in both the thermal shock life and its stability.

Same-spot micro-ECM based on constant-accelerated movement of the electrode

ABSTRACT An injector nozzle needs a precision upside-down tapered-microhole, and the nozzle material is often a high temperature corrosion resistant alloy that is very difficult to machine. In this study, a same-spot micro-ECM technique with the electrode in “constant-accelerated movement” was proposed. Insulated by electrophoretic deposition, an ultra-fine electrode was inserted deep into the hole and subject gradually to withdrawal from the hole at constant rpm and acceleration. The electric flux intensity acting on the hole-wall gradually decreased and so did the material dissolution rate on the hole-wall, thus creating an upside-down tapered hole with the desired taper-rate. The experiments’ results showed that upside-down tapered holes with taper-rates of T(a=1) = 0.094 (Ra 0.593 μm) and T(a = 2) = 0.02 (Ra 0.435 μm) were produced when the electrode was subject to constant-acceleration withdrawal at 1.0 and 2.0 μm/s2, respectively, and respective spray angles of 31° and 23° were created. The proposed technique is commercially promising in industry.

Advanced Numerical Analysis of In-Cylinder Combustion and NOx Formation Using Different Chamber Geometries

In diesel engines, emission formation inside the combustion chamber is a complex phenomenon. The combustion events inside the chamber occur in microseconds, affecting the overall engine performance and emissions characteristics. This study opted for using computational fluid dynamics (CFD) to investigate the combustion patterns and how these events affect nitrogen oxide (NOx) emissions. In this study, a diesel engine model with a flat combustion chamber (FCC) was developed for the simulation. The simulation result of the heat release rate (HRR) and cylinder pressure was validated with the experimental test data (the engine test was conducted at 1500 rpm at full load conditions). The validated model and its respective boundary conditions were used to investigate the effect of modified combustion chamber profiles on NOx emissions. Modified chambers, such as a bathtub combustion chamber (BTCC) and a shallow depth chamber (SCC), were developed, and their combustion events were analysed with respect to the FCC. This study revealed that combustion events such as fuel distribution, unburnt mass fractions, temperature and turbulent zones directly impact NOx emissions. The modified chambers controlled the spread of combustion and provided better fuel distribution, improving engine performance and combustion rates. The SCC (63.2 bar) showed peak pressure rates compared to the FCC (63.02 bar) and BTCC (62.72 bar). This study concluded that the SCC showed better results than other chambers. This study further recommends conducting lean fuel mixture combustion with chamber modifications and optimising fuel spray, such as by adjusting the fuel injection profile, spray angle and injection timing, which has a better tendency to create complete combustion.

Prediction of operating state of hydrocyclones using vibrometry and 1D convolutional neural networks

Due to high processing capacity requirements and constraints on industrial water utilization, operation of hydrocyclones at higher feed solid concentration is often unavoidable. Hydrocyclone operation at such higher feed solid concentrations is accompanied by the risk of onset of rope discharge, adversely affecting both the size separation and thickening performance of the hydrocyclone. Numerous condition monitoring efforts have been reported in the literature regarding the development of online techniques for detection of roping in hydrocyclones. However, detection of roping, post its commencement, only ever allows for corrective maintenance in the form of measures taken for shifting the discharge back to the desired spray profile. This study focuses on the characterization and online detection of a transition discharge state which precedes the onset of roping, thereby making the prevention of onset of roping, possible. The transition discharge state was delineated from the conventional spray and rope discharge types based upon the observed differences in the decay rates of underflow discharge spray angles with increasing feed solid concentrations. A binary classification model (spray – rope) and a ternary classification model (spray – transition – rope) were developed with a 1D Convolutional neural network architecture capable of taking 5 secs of tri-axial (3-channel) vibration signal data as input, and outputting the predicted discharge type labels with an accuracy of 97.31 % and 94.94 %, respectively.

Study on Urea Crystallization Risk Assessment and Influencing Factors in After-Treatment System of Diesel Engines

In order to meet the increasing pollutants discharge standard, the selective catalytic reduction (SCR) module in the diesel engine after-treatment system is an important means to reduce nitrogen oxide (NOx) emissions. SCR systems are prone to urea crystallization at lower temperatures, especially during the cold-start conditions of diesel engines. In this study, we use the diesel engine after-treatment system test bench to obtain the boundary parameter of the simulation modules, and the urea crystallization risk assessment model of the diesel SCR system is established. Comparing the computational fluid dynamics (CFD) results with the test bench results, it is shown that the predicted urea film distribution of the assessment model is in good agreement with the experimental results. In order to clarify the various factors that affect the urea crystallization risk, this paper conducts a simulation analysis on a nozzle and mixer structure and operating parameters. The CFD results indicate that the increase in urea spray time will increase the maximum urea film thickness on the SCR system mixer surface. Exhaust temperature is the most important influencing factor. When the diesel engine exhaust temperature increases from 190 °C to 300 °C, the maximum urea film thickness decreases by 32 and the urea film mass accumulation decreases by 5%. Exhaust flow has a small impact on urea crystallization risk. When the exhaust flow increases from 300 kg/h to 600 kg/h, the maximum urea film thickness decreases by 39% and the urea film mass accumulation decreases by about 1%. In addition, urea spray rate, nozzle numbers, spray angle, and spray cone angle are also factors that affect urea crystallization risk.

Spray deposition in an artificial grapevine canopy as affected by spray angle regulation systems of radial airflow air-assisted sprayers

As the most critical factor affecting pesticide application efficiency and drift risk, the airflow characteristics of air-assisted sprayers have been of great concern. This study compared seven assisted airflow angle regulation methods regarding within-canopy deposition quality and off-target losses to the ground and behind the target canopies, including a newly proposed airflow swing device, three types of directional housings, and airflow deflector settings. An artificial grapevine canopy and a multiple-tracer methodology were used to evaluate deposition. Results showed that airflow angle regulation methods caused significant differences in canopy deposition and off-target losses (p < 0.001). The sprayer equipped with 0° housing had the highest deposition on the canopy (122.27 μg cm−2), followed by the sprayer equipped with the −30° housing (99.26 μg cm−2). The sprayer equipped with both airflow swing devices and optimal deflectors had a deposition of 87.76 μg cm−2. The radial airflow air-assisted sprayer without any airflow interventions caused the highest off-target losses, reaching 31.95% of the total spraying volume. The optimal deflector setting was conducive to reducing ineffective losses, but it also deteriorated the deposition uniformity on the canopy. Significantly, the airflow swing device improved the deposition uniformity on the abaxial side of the leaves to 23.89%, which can provide a reference for future optimization of new air-assisted sprayers.

Spray characteristics of a self-aspirating ethanol ejector for high-efficiency combustion-based thermoelectric micropower generators

Low energy conversion efficiencies of combustion-based micropower generators due to parasitic losses continue to be a persistent challenge that limits their practical applications. This work puts forward a new strategy of liquid fuel delivery to a microcombustor with improved atomization and minimum parasitic energy losses. In the present work, a self-aspirating spray ejector is developed, providing continuous ethanol fuel delivery in the form of micron-sized droplets to a microcombustor of ∼ 1.0 kW thermal input capacity. The ejector base- setup works on the principle of generating a low-pressure zone through gas expansion, leading to the self-aspiration of ethanol fuel. The emerging annular ethanol film manifests a shear instability at the liquid–gas interface and subsequently breaks up into ligaments and fine micron-sized droplets. It was observed that the hydrostatic pressure of gas and aerodynamic Weber number (We) significantly affect the ethanol ejection rate, Sauter mean diameter (SMD), droplet distribution, and entrainment ratio of the spray ejector. The spray characteristics, such as mean droplet velocity and spray angle, are mainly governed by a single parameter, i.e., aerodynamic Weber number (We). The maximum power consumption for the spray ejector during the steady-state operation is ∼ 0.1 % of thermal input. The present investigation suggests that the self-aspirating spray ejector generates a fine and fully developed spray with ultra-low energy input requirement and, thus, can be a potential candidate for the development of high-efficiency combustion-based thermoelectric micropower generators.

Study on the influence of airflow disturbance on spray atomization

The droplet distribution characteristics are one of the key factors that determine the dust suppression effect of spray system. In order to study the droplet distribution characteristics under different working conditions, the influence mechanism of wind speed and spray angle on droplet distribution characteristics was studied based on Fluent software. The results show that the increase of wind speed and spray angle will increase the lateral momentum of droplets, resulting in the increase of longitudinal height and lateral length of spray belt. The change of spray angle causes the change of the distribution ratio of transverse momentum and longitudinal momentum of droplets. With the increase of spray angle, the transverse momentum of droplets increases and the longitudinal momentum decreases, resulting in the increase of the longitudinal height and length of spray belt. In engineering practice, attention should be paid to the coordinated control of nozzle height, spray angle and airflow speed.

Optimization of the current spray angle of the nozzles of the adaptive distribution system of a single-support boom sprayer

One of the unsolved problems of plant protection mechanization is the uneven distribution of pesticides due to vertical vibrations of the sprayer boom. At the same time, the variation of the treatment band with each sprayer can reach 38% or more. This issue is even more relevant for single-support wheelbarrow sprayers, which are used in breeding and primary seed production. This significantly affects the quality of the technological operation. A technical solution to this problem could be the use of sprayers with variable spray geometry. Such a solution requires an analytical substantiation of the dependence of the spray pattern angle on the position angle of the sprayer boom. The purpose of the proposed research is to develop a technique for optimizing the spray angle of sprayer nozzles, taking into account the vertical vibrations of the distribution rod. Geometric and mathematical modeling, theoretical analysis of qualitative and agrotechnical parameters of spraying, substantiation of the laws of the technological process of spraying based on the known laws of physics and classical mathematics, as well as a method of nomogramming functions of several variables were used as scientific methods. It has been established that the uniformity of the application of protective equipment is determined not only by the position of the rod in the vertical plane, but also by the value of the root spray angle, the height of the installation of the sprayer and its position relative to the center of oscillation of the rod. An analytical expression is derived that relates the current width of the processing strip from one sprayer to the specified factors. The dependence of the optimal spray angle on the angle of inclination of the sprayer boom is also proposed. A nomogram has been developed that takes into account permissible deviations in the uneven distribution of the working fluid during spraying. The optimization technique is new. It is applicable to the development of software for the sprayer control complex, which is equipped with an adaptive pesticide distribution system in changing conditions.