Spray Field Research Articles

Numerical simulation for spray spatial distribution of swirl nozzle and its target dustfall area prediction.

The droplet breakup and distribution of the internal flow field and external spray field of a nozzle were obtained under different pressures. The thickness of the liquid film increased with pressure as a quadratic function. The maximum value of 0.281mm at 2MPa decreased to 0.172mm at 10MPa, equivalent to 38.8% decrease. The MATLAB was used to obtain the particle size distribution characteristics of the droplets under different pressures. At 2MPa, droplet breakup dominated the axial interval [0-700mm]. With the increase of pressure, D50 distribution as a whole continues to decrease, 2-6MPa change, the particle size reduction is larger, every increase of 2MPa reduced by about 15%. 6-10MPa change, the particle size reduction is smaller, every increase of 2MPa reduced by about 8%. A model to predict the optimal dust reduction areas under varying pressures was developed. The prediction results indicate that at pressures of 5MPa and 9MPa, the target dust removal areas were [344mm, 710mm] and [424mm, 942mm] along the axial direction, respectively.

Evaluation of droplet deposition parameters based on the Genetic-Otsu algorithm.

Pesticide spraying is a cost-effective way to control crop pests and diseases. The effectiveness of this method relies on the deposition and distribution of the spray droplets within the targeted application area. There is a critical need for an accurate and stable detection algorithm to evaluate the liquid droplet deposition parameters on the water-sensitive paper (WSP) and reduce the impact of image noise. This study acquired 90 WSP samples with diverse coverage through field spraying experiments. The droplets on the WSP were subsequently isolated, and the coverage and density were computed, employing the fixed threshold method, the Otsu threshold method, and our Genetic-Otsu threshold method. Based on the benchmark of manually measured data, an error analysis was conducted on the accuracy of three methods, and a comprehensive evaluation was carried out. The relative error results indicate that the Genetic-Otsu method proposed in this research demonstrates superior performance in detecting droplet coverage and density. The relative errors of droplet density in the sparse, medium, and dense droplet groups are 2.7%, 1.5%, and 2.0%, respectively. The relative errors of droplet coverage are 1.5%, 0.88%, and 1.2%, respectively. These results demonstrate that the Genetic-Otsu algorithm outperforms the other two algorithms. The proposed algorithm effectively identifies small-sized droplets and accurately distinguishes the multiple independent contours of adjacent droplets even in dense droplet groups, demonstrating excellent performance. Overall, the Genetic-Otsu algorithm offered a reliable solution for detecting droplet deposition parameters on WSP, providing an efficient tool for evaluating droplet deposition parameters in UAV pesticide spraying applications.

From pollution to resource: advancing swine waste treatment in the USA

Concentrated animal feeding operations (CAFOs) have led to environmental challenges, specifically waste management. Swine CAFOs generate large amounts of waste, requiring proper treatment to avoid air and water pollution. Conventional waste management technologies, such as lagoon and spray field systems, do not prevent air and water pollution impacts. Research for the past few decades led to recommendations for waste treatment technologies superior to lagoons and spray fields. Private environmental sustainability initiatives focused on reducing greenhouse gas emissions in the food supply chain have implemented biogas digester projects for capturing methane in covered swine lagoons to reduce greenhouse gas emissions. However, research indicates that methane capture alone does not solve the broader pollution issues associated with lagoon and spray field systems still in use at these CAFOs to dispose of digested effluents. The Environmentally Superior Technologies (EST) initiative in North Carolina set public standards to eliminate waste discharge, reduce atmospheric emissions, and control odors and pathogens. Research has confirmed that technologies coupling solids separation with water treatments to remove volatile organic carbon, pathogens, and reactive forms of nitrogen can meet EST standards. A designated EST—the Super Soil System—substantially reduced odor by 99.9%; pathogens by 99.99%, nutrients (phosphorus and nitrogen) by >90%, and heavy metals (cooper and zinc) by 99%. The ammonia emissions were reduced by 94.4% for the warm and 99.0% for the cool season with respect to a conventional lagoon system. Corresponding greenhouse gas emission reductions were 96.7%. Components of designated EST can be applied to retrofit covered lagoons and anaerobic digestion systems with significant environmental benefits. Recommendations are proposed, based on the collective experience with EST and current trends in animal production concentration, for environmentally safe technologies to handle excess manure produced in the USA.

MRI and HR-MAS NMR spectroscopy to correlate structural characteristics and the metabolome of Fiano and Pallagrello grapes with the action of field spray preparation 500 and the soil spatial microvariability

BackgroundA number of Italian grape berry varieties, such as Fiano (F) and Pallagrello Nero (P), represent National strategic products. Therefore, it is important to identify soil conditions emphasizing their peculiar characteristics as well as find innovative and sustainable treatments improving their compositional and nutraceutical quality. The field spray preparation 500 is a biodynamic product that is presumed to serve as biostimulant on the vine. However, so far, the scientific results probing its effectiveness are still lacking. Moreover, it is necessary to establish a reliable relationship between the grape quality and the spatial microvariability of the vineyard’s soil. On this basis, the main objective of this work consisted in correlating structural and morphological characteristics (via MRI), the primary metabolome (via semi-solid state HRMAS NMR) and important nutraceutical parameters (total phenols and antioxidants via DPPH assay) of F and P grapes with both the action of preparation 500 biostimulant and the vineyard soil microvariability, based on soil apparent electrical conductivity.ResultsHRMAS enabled the identification of the primary metabolome of F and P. The elaboration of 1H NMR spectra through chemometrics revealed significant changes in F and P grapes, accounting for both soil microvariability and the application of field spray (the latter also confirmed by PLS-DA and Heat-map clustering). Interestingly, for both F and P it was observed a significantly lower content of carbohydrates after biostimulant treatment while MRI revealed diagnostic structural and internal details of intact grapes. The combined use of proton parametric indices, such as relaxation times and diffusion coefficients, indicated alterations induced in grapes by both the spatial microvariability of the soil and the effects of investigated biostimulant. Interestingly, a tight correlation was found between MRI transverse relaxation time and the contents in total phenols and antioxidants.ConclusionsOur results have proven that both soil spatial microvariability and the application of field spray preparation 500 significantly affect the structural, metabolomic and nutraceutical characteristics of grapes. Moreover, the preparation 500 treatment has increased the nutraceutical value of grapes. Importantly, these data may be potentially used to promote and protect biodynamic grape and predict the quality of the resulting wines.Graphical

An Improved Comprehensive Atomization Model for Pressure Swirl Atomizers

This study presents an improved comprehensive atomization model for a pressure swirl atomizer. The model integrates internal flow predictions, linear instability analysis of a swirling annular liquid sheet, primary atomization sub-model, and droplet velocity sub-model. Measurement data combined with the inviscid theory model predict the internal flow, providing liquid sheet velocity and thickness at the atomizer outlet. The dispersion relation of surface disturbances is obtained through linear instability analysis. A primary breakup predictive model for particle size distribution is constructed based on the wavelength and growth rate within the full unstable wavenumber range of the dispersion relation. Assuming uniform circumferential distribution and a normal distribution of spray angles, the droplet velocity is assigned according to the liquid sheet velocity. The model is implemented into Eulerian–Lagrangian simulations as initial conditions for discrete phase droplets to simulate the spray field. Results show the model can accurately predict the Sauter mean diameter with an error of less than 6% and effectively predicts the spray structure and spray cone angle. The dependency of the model on its parameters is also studied, determining that the values of the ligament constant and dispersion angle have an obvious impact on the prediction of Sauter mean diameter and spray structure.

Study on the spray characteristics of transverse jets with elliptical nozzles in supersonic crossflows using the volume of fluid–discrete phase model

The atomization characteristics of liquid jets injected transversely into a supersonic crossflow significantly affect the performance of scramjet engines. Existing research on this topic has mainly focused on circular nozzles, while the influence of nozzle geometry, particularly elliptical nozzles, has received relatively limited attention. Therefore, this study employs a numerical simulation method coupling the volume of fluid and discrete particle model to investigate the breakup and atomization characteristics of transverse liquid jets from elliptical nozzles with different aspect ratios under supersonic crossflow conditions, as well as the total pressure loss. The simulation model is validated against experimental data obtained from a pulse wind tunnel, including measurements of the liquid jet penetration depth and the Sauter mean diameter (SMD). The results indicate that for elliptical nozzles with an aspect ratio (AR) greater than 1, columnar breakup occurs earlier, and the columnar breakup length is shorter compared to circular nozzles. As the AR increases, the jet penetration depth decreases, while the spray expansion angle increases. Furthermore, the SMD of the atomized spray field from the circular nozzle is larger than that from the elliptical nozzles, and the SMD of the spray field is smallest for an elliptical nozzle with AR of 4. Finally, the elliptical nozzles exhibit a higher total pressure recovery coefficient, indicating reduced total pressure loss in the combustion chamber. This reduction in pressure loss is expected to improve the thrust performance of the scramjet engine.

Effect of Process Parameters on the Substrate Surface in Cold Spray Coating

In this work, we used the cold spray process to coat a surface and investigated to understand the influence of various process parameters on the substrate surface temperature. The parameters we varied included the pressure, temperature, particle size, and particle speed of the titanium powder that we used in the cold spray coating process. It is a unique finding in the field of cold spray coating. For the substrate material, we chose steel and simulated the spray geometry using a two-dimensional axisymmetric model. This model employed a k-ɛ turbulence model with an implicit pressure-based solver of second-order precision. Our observations revealed that the surface temperature of the substrate reached its maximum value when the length of the injector was 15 mm. We also found that the most compatible length for the nozzle barrel was equal to the length of the particle injector.

Spray characteristics of elliptical orifice spray in diesel engine under air movement conditions

The development of high-quality mixture is a critical requirement for achieving high-efficiency and low-emission diesel engines, and fuel injection system performance improvement and in-cylinder airflow organization are crucial ways for achieving high-quality mixture. The elliptical nozzle is used as the research object in this research, and numerical simulation is utilized to investigate the effect of different airflow speeds and directions on the atomization characteristics of the elliptical nozzle jet, in order to provide a theoretical basis for the engineering application of the elliptical nozzle in diesel engines. The results show that under the same airflow conditions, the vertical penetration distance of the spray decreases while the horizontal penetration distance increases with the use of elliptical orifices, the surface wave perturbation on the windward side is more violent, and reduce spray field the Sauter Mean Diameter (SMD). The spray projected area grew by 13.5%, the spray SMD dropped by 14.8%, and the vertical penetration distance of the spray with elliptical orifices fell by 18% with an increase in airflow velocity from 0 to 20 m/s. When the airflow direction and the spray direction were at a 90° angle and the SMD was lower than that of the circular orifice by 12.9%. The angle between the airflow direction and the short axis of the elliptical orifice was 30°when the spray projection area was larger, the perturbation of the spray body was more intense, and the surface wave amplitude was larger.

Alternaria alternata Pathogen from Cuscuta japonica Could Serve as a Potential Bioherbicide.

Dodder (Cuscuta spp.) is a dangerous parasitic plant that causes serious damage to crop production and is challenging to eliminate. Herbicide application is a common strategy to control dodder in the field, but it is costly, ineffective, and further results in hazardous outcomes. Therefore, our study aims to identify the potential pathogens in naturally occurring dodder infections which may provide efficient biocontrol options. In this regard, the pathogens were isolated from the infected plants, their pathogenicity was validated through inoculation, and the optimal culture conditions for their growth were identified by determining the pathogenicity difference. The pathogenicity range was determined in vitro using the leaves of common horticultural plants and crops. Furthermore, a small range of horticultural plants parasitized by Cuscuta reflexa in the field were inoculated with the pathogen to determine their biosafety and biocontrol potential, and the pathogens were identified by morphological and molecular characterization. We found 7 strains that were isolated after pathogen enrichment culture. Among them, Cbp6 and Cbp7 showed the highest pathogenicity against C. reflexa. After testing the inoculation of more than 50 species of plants, only 9 species showed varying degrees of lesions on leaves, which proved the high biosafety for common plants. Field spraying of these pathogens showed a good control effect on C. reflexa after 21 days; the disease severityreached 66.0%, while its host plant did not display obvious symptoms. In conclusion, the pathogens Cbp6 and Cbp7 were identified as Alternaria alternata, and the results of this study provide a theoretical basis for the biological control of dodder.

Spray field characteristics and the effect of spray-local exhaust ventilation on the control of high-temperature buoyant jets

Process equipment limitations resulted in constraints on the location of the exhaust hood, which in turn caused escape of high-temperature buoyant jets. In response to this situation, spray system is installed as an auxiliary measure to improve the control effect by spray cooling and weakening the momentum. However, the correlation between spray parameters and its atomization characteristics in high temperature ambient is not clear, reasonable spray parameters directly affect the performance of spray-local exhaust ventilation (SLEV). In this study, we discuss the spray field characteristics under the action of high-temperature buoyant jets, the effects of exhaust and spray parameters on the capture efficiency of SLEV, combined with orthogonal test to get the optimization order. Influences discussed include: exhaust velocity, spray pressure, and nozzle hole diameter. The results showed that SLEV provides superior control of high-temperature buoyant jets, up to two times that of the local exhaust ventilation (LEV). Compared to nozzle hole diameter, the spray pressure significantly effects spray field characteristics. Under high-temperature buoyant jets conditions, the statistical mean diameter obeys a power function relationship with spray pressure, and the capture efficiency was 75% as the spray pressure of 2.0 MPa and nozzle hole diameter of 1.8 mm. The factors affecting the performance of SLEV were found to be exhaust velocity > spray pressure > nozzle hole diameter by range analysis. The research results are expected to contribute to the optimization and enhancement of the SLEV.

Effects of nozzle diameter on marine fuel injection and deflagration performance

The marine fuel injection and deflagration performance with different nozzle diameters in large compartments are researched in this work. The results show that marine fuel could quickly form a stable fuel spray field. Increasing nozzle diameter dramatically enhances the fuel spray concentration and aggravates the fuel spray deflagration degree, resulting in rapid increases in flame propagation speed, deflagration overpressure, and deflagration temperature. A larger nozzle diameter causes the deflagration flame to propagate further forward. With the increase of deflagration time, the flame propagation speed shows a trend of first rising and then decreasing, with fluctuations. When the nozzle diameter is small, the overpressure declines toward the back. In the case of large nozzles (≥0.8 mm), the overpressure distribution in the compartment fluctuates greatly, with a tendency to increase first and then decrease. Furthermore, deflagration peak overpressure ascends linearly with the logarithm of fuel spray concentration. The peak deflagration overpressure is 1.875 MPa with 1.0 mm nozzle diameter. The deflagration temperature is highest at the center of the deflagration. The research results can guide the assessment and prevention of fire and deflagration accidents on ships.

Experimental study on the penetration and evaporation characteristics of a liquid kerosene jet in the supersonic crossflow

The penetration and evaporation characteristics of a liquid kerosene jet in the supersonic crossflow were experimentally investigated in this study. The experiments were carried out in both cold and high-enthalpy inflows. Detailed spray images were obtained using planar laser scattering techniques. The structures of the spray field were further analyzed on the basis of high spatial and temporal resolution images. The results show that the atomization and evaporation characteristics of a liquid kerosene jet are related to the crossflow temperature, liquid–gas momentum flux ratio, and injection distance. It is found that the breakup process of a liquid jet is accelerated in the high-enthalpy inflow. To accurately describe the maximum flow distance along the direction that kerosene can reach in the state of droplets, the survival distance is defined. It is revealed that the penetration depth and survival distance of the liquid kerosene jet decrease clearly with increase in the crossflow temperature. For the cavity-based combustor, the liquid kerosene jet can mix more sufficiently in the cavity region by reducing the injection distance and liquid–gas momentum flux ratio.

Influence of electric field, liquid film thickness, and sodium chloride deposition on atmospheric corrosion of Cu

Printed circuit boards (PCBs) are prone to failure due to the influence of environmental factors such as humidity, salt spray, and electric fields during usage. As the lead pitch of PCBs decreases and these environmental factors become challenging to control, corrosion becomes unavoidable. This study used a self-built thin liquid film–electric field coupling environment in an in situ electrochemical testing apparatus. PCB-Cu electrodes were evaluated using open-circuit potential and polarization curve tests on the thin liquid film. This study systematically investigated the effects of external electric field bias, sodium chloride deposition, and liquid film thickness on PCB-Cu corrosion. The results showed that increased bias promoted Cu corrosion in the coupled environment and altered electrode reactions. The cathodic process transitioned from activation control at 0–1 V to hydrogen evolution electrochemical control at 3 V for electrode reactions. Increased sodium chloride deposition enhanced the Cu corrosion rate in the coupled environment primarily due to Cl− damaging the corrosion product film. Under different liquid film thickness conditions, the corrosion rates can be ranked as 200 μm > 300 μm > 100 μm, with 200 μm exhibiting the highest corrosion rate and marking the transition point from the cathodic to anodic control of the corrosion reactions. Orthogonal analysis results indicated that bias was the most influential factor affecting Cu corrosion, followed by liquid film thickness and sodium chloride deposition.

Analysis of parameters for spray-local exhaust ventilation (SLEV) to minimize high-temperature smoke pollutants and reduce energy consumption

Industrial buildings often face limitations in placing local exhaust ventilation (LEV) near pollution sources, which can lead to ineffective control of high-temperature smoke. This study explores the integration of spray with local exhaust ventilation (SLEV) as a solution for smoke control and energy savings. The research identified a design law for spray parameters and developed a formula to calculate SLEV ventilation flow rate that considers the impact of spray. Results indicate that the spray field overlapping coefficient plays a key role in characterizing the position and spacing of multi-nozzles. As the spray field overlapping coefficient increases, the spray dust reduction performance indicator linearly increases, while the capture efficiency follows a pattern that aligns with the Boltzmann curve model. The optimal range for the spray field overlapping coefficient to achieve high efficiency in SLEV is between 0.45 and 0.55. The formula for ventilation flow rate calculation is applicable to common conditions with smoke velocities ranging from 4 to 12 m/s (Ar: 0.0149–0.1339). SLEVs demonstrate a 35.22 % improvement in dust removal efficiency and over 20 % energy savings compared to LEVs, contributing to the development of high-efficiency, energy-saving systems for sustainable industrial production.

Experimental study of single droplet impingement on a thin liquid film under a non-uniform electric field

Droplet impingement on a thin liquid film has been extensively applied in the field of spray cooling due to its powerful heat and mass transfer properties. In this study, the impact dynamics of a single droplet impacting on a thin liquid film under a non-uniform electric field was experimentally investigated. Ethanol was employed as the working fluid, and the impact behaviors were captured by high-speed photography technology. The results showed that the impact process sequentially exhibits the phenomena of the liquid crown and liquid column. Five typical crown patterns were identified, and the unique “jet crown” mode was first reported. The crown dimension analysis indicated that the maximum crown height increased with the increase in electric Bond number (0 ≤ BoE ≤ 583.48), while the crown width was likely independent of BoE. Furthermore, this study provided the splashing threshold of the crown under a non-uniform electric field by coupling the BoE with an empirical formula determining the splashing threshold. In addition, a unique phenomenon of jetting liquid columns was obtained. During the ascent phase of the liquid column, the vertical downward acceleration of the liquid column was significantly greater than the gravitational acceleration. The presence of an electric field introduced fluctuations in the liquid column's acceleration, causing the direction of acceleration to alternate between upward and downward. This study contributes to a deeper understanding of the physical mechanisms underlying the electric field modulation of droplet impingement behavior.

BRIEF OVERVIEW OF METHODS FOR PRODUCING TiSiCN COATINGS AND THE METHOD OF REACTIVE PLASMA SPRAYING

Modern materials science sets itself the task of developing new materials with multifunctional coatings. Materials with such coatings are widely used in various fields of technology: construction and energy, microelectronics, aviation and others. The main reason for the emergence and development of technology for applying multifunctional protective coatings is the desire to increase the durability of parts and assemblies of various machine mechanisms. Wear-resistant hard coatings based on transition metal nitrides and carbonitrides are widely used to extend the life of forging and extrusion dies and high-speed machining tools. Over the past two decades, the widespread use of these coatings has stimulated and supported the development of new processes and materials in an attempt to further improve their properties. Among these coatings, the higher hardness, excellent oxidation resistance and high thermal stability of coatings such as TiSiN and TiSiCN make them the most promising candidates for demanding tribological applications. In addition, TiSiCN coating is a promising material used in marine environments due to its excellent anti-wear and corrosion resistance, as well as high hardness and low friction coefficient. These combinations of properties make TiSiCN coatings potential candidates for protective layers in the automotive and petroleum industries.The article briefly examines the possibilities of producing TiSiCN coatings using different deposition methods to control the properties of the resulting films and the features of the reactive plasma spraying method. The work describes the most common methods and technologies for producing carbonitride coatings currently used. The latest developments and current trends in the field of plasma spray coating technologies are reviewed, taking into account important innovations for industrial coatings. New conclusions that were obtained as a result of fundamental and applied research in physics or chemistry are based on them. The article provides a comparative review of the characteristics of obtaining wear-resistant TiSiCN coatings and the features of using reactive plasma spraying to obtain wear-resistant coatings. Based on an analysis of the literature, it can be argued that the further development of reactive plasma technology is associated with the development of a new resource-saving method for the formation of composite coatings with increased corrosion and tribological characteristics, which corresponds to the development trends of world science.

Experimental study on the droplet size distribution of radial orifice gas–liquid pintle injector at ambient pressure

Pintle injector can achieve reliable and stable combustion of propellant, thereby greatly reducing the design difficulties of the combustion chamber. Droplet size, which has a great influence on the subsequent combustion process with high ambient pressure, is an important atomization characteristic. However, the influence of ambient pressure on the droplet size distribution of radial orifice gas–liquid pintle injector has not been extensively investigated. At the ambient pressures of 0.4–0.6 MPa, the tests were carried out in the ambient pressure chamber with the liquid mass flow rates of 10–15 g/s and the gas mass flow rates of 7.2–15 g/s. Droplet size was measured by Spraylink High-speed Spray Particle Size Analyzer. The results indicate that droplets Sauter mean diameter (SMD) increases with axial and radial distances. A dimensionless parameter N, which represents the ratio of the vertical component of droplet aerodynamic force to gravity, is defined to analyze the reasons for the change trend of axial droplet size in the central reflux zone of the spray field where droplet size increases with axial distance. Droplets SMD increases with ambient pressure and liquid mass flow rate, and decreases with increasing gas mass flow rate. Furthermore, droplets SMD is positively correlated with local momentum ratio (LMR), whereas negatively correlated with Weber number (We). The empirical formula for axial cross-sectional droplets SMD was fitted with a determination coefficient of 0.993. The results can help elucidate droplet spatial distribution and the influences of several working parameters on the spray characteristics, thereby facilitating the design of pintle injector.

An integrated nanofiller spray and nanosecond pulse electrically-assisted method for synergistically interlaminar toughening and in-situ damage monitoring of CFRP composites

Nanomaterials have already been explored their potential for interlaminar toughening and crack-monitoring capabilities within the field of composite materials. However, efficient enhancement of interlaminar fracture toughness remains an unresolved challenge. Herein, a novel integrated filler spray and nanosecond pulsed electric field (nsPEF)-assisted curing technique is proposed for the fabrication of high-performance composite material system for the first time. The spraying technique proves to be an effective approach for depositing fillers, including carbon nanotubes (CNTs), graphene nanoplatelets (GNPs), and carbon nanofibers (CNFs), onto carbon fiber prepreg. Meanwhile, the nsPEF-assisted technique is utilized to enhance the wettability of resin to fiber, thus reducing void defects. The efficacy of this integrated technique is evidenced by the particularly low content of fillers (0.047 wt%). The experimental results show a substantial reduction of porosity in the composite by 49.36% (from 1.56% to 0.79%). Meanwhile, the mode I initiation and steady-state toughness of samples with CNTs and GNPs are remarkably improved by up to 47% and 82%, respectively, compared to the baseline. This represents the most significant improvement reported to date for non-functionalized CNTs and GNPs at such low concentrations. Moreover, the relative electrical resistance variation (ΔR/R0%) of CNT/GNP sensors used for in-situ damage sensing increased by ∼ 14%. This work pioneers the investigation of the synergistic effects of two promising techniques for preparing composite materials, offering advantages in terms of simplicity, multifunctionality, and the potential for industrial scalability.

Spray performance of flexible shield canopy opener and rotor wind integrated boom-sprayer application in soybean: effects on droplet deposition distribution.

Canopy density is high during mid-to-late soybean growth as a result of dense planting to improve yield, which seriously affects the control of pests and diseases. The dilemmas of difficult droplet penetration, nonuniform deposition, and droplet drift in field spraying remain challenges to the precise control of droplet distribution. This paper proposed a novel spraying application mode combined flexible shield canopy opener (FSCO) with rotor wind. The design of the key components of the new boom-spraying machine are described. The effects of the comparative spraying modes on spray deposition and droplet drift were studied in a field validation test to explore the feasibility of the novel spraying application. The study found that droplet coverage inside the soybean canopy was significantly affected by spraying mode, rotor wind speed and opener depth. The spraying operation that used the FSCO and rotor wind integrated mode was optimal for droplet uniformity on the adaxial and abaxial surfaces of the canopy leaves, with droplet uniformity indices of 0.966 and 0.934, respectively. At a rotor wind speed of 6 m s-1 and opener depth of 15 cm, the soybean canopy droplet coverage uniformity effect achieved the highest composite score of 0.937. The spraying mode used in this study improved droplet coverage uniformity by 82.30% and droplet anti-drift performance improved by 99.73% compared to the conventional boom-spraying mode. The study shows validity of the spraying mode combined FSCO with rotor wind to open dense canopy and improved droplet deposition uniformity in canopy and anti-drift performance. © 2024 Society of Chemical Industry.

A method for the prediction of the atomization diameter distribution of the spray generated by swirl nozzles

Atomization is an indispensable process for achieving high-efficiency conversion in various energy applications. This study proposes a novel and simplified method to predict the droplet diameter distribution along the spray direction during atomization by swirl nozzles. The method considers the droplet breakup and coalescence and consists of three sub-models, i.e., the primary breakup model, the secondary breakup model, and the velocity model. The prediction method is verified by droplet sizing experiments using typical swirl nozzles. Combining the experimental results, the atomization process from fluid to droplets is analyzed in-depth. Results show that the present method can predict the droplet diameter distribution along the spray direction, with an average error of droplet diameter of approximately 7.7%. The effects of the orifice diameter and water supply pressure of nozzles on droplet diameter distribution are discussed. The droplet diameter decreases in the whole spray field as the water supply pressure rises. When the orifice diameter increases, the mass flow rate and Sauter mean diameter increase in the near-orifice region. However, the droplet diameter difference in nozzles reduces as the position is far away from the orifice. The proposed method can aid the design of some critical energy devices containing the atomization process.