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The suitability of High pressure nozzles in terms of impact upon targeted surfaces has indicated its effectiveness for the cleaning of oil production tubing scale, which has recently attract wider industrial applications considering its efficiency, ease of operation and cost benefit[1]. In the Oil and gas production, these nozzles are now used for cleaning the scale deposits along the production tubing resulted mainly from salt crystallization due to pressure and temperature drop. Detailed characterizations of flat-fan nozzle in terms of droplet sizes and mean velocities will benefit momentum computations for the axial and radial distribution along the spray width, with the view of finding the best stand-off distance between the target scale and the spray nozzle. While the droplet sizes and the velocities determine the momentum at impact, although measuring droplet sizes has been known to be difficult especially in the high density spray region [2], still laboratory characterization of nozzles provide a reliable data especially avoiding uncontrollable parameters[3].While several research consider break up insensitive to the cleaning performance, this research investigate the experimental data obtained using Phase Doppler Anemometry (PDA) which led to established variation in momentum across the spray width thus, non-uniformity of impact distribution. Validation model was then developed using Fluent which verify the eroded surfaces of material using the flat-fan atomizer to have shown variability in the extent of impact actions due to kinetic energy difference between the center and edge droplets. The study’s findings could be useful in establishing the effect of droplet kinetic energies based on the spray penetration, and will also add significant understanding to the effect of the ligaments and droplets effects along the spray penetration in order to ascertain their momentum impact distribution along the targeted surface.

Spray nozzle selection contributes to improved postemergence herbicide crabgrass control in turfgrass

Abstract. Optimizing aerial spray applications requires proper setup of the sprayer system, particularly with respect to nozzle selection and operation, which significantly affects spray deposition, product efficacy, and spray drift. Droplet size from an aerial application is a function of the combination of nozzle type, nozzle orifice size, spray pressure, orientation angle, and airspeed of the aircraft. A set of computational models for 14 commonly-used aerial application nozzles were developed and released for use by applicators. These models allow applicators to determine the droplet size characteristics associated with their specific nozzle and operational setup, determining the proper combination of orifice, pressure, orientation, and airspeeds from 22 to 54 m/s (50 to 120 mph), which are commonly-associated with applications made from rotary wing aircraft (i.e., helicopters). Both spreadsheet and smartphone user interfaces are available for applicators to use to ensure that their application conforms to the legal droplet size requirements specified on an agrochemical product label. Keywords: Aerial application, Atomization, Droplet size, Droplet size models, Spray nozzles.

<div class="htmlview paragraph">A single nano-spark back light photography method has been developed to record the image of non-evaporating diesel sprays injected into high pressure nitrogen gas. Relatively clear image of fine droplets and spray was obtained. An image analysis method has been developed to quantify the droplet characteristics which are in focus, such as droplet size and shape. Spatial and temporal distribution of droplets has been clarified. It was observed that the number of droplets around the nozzle tip region decreases by time, however a large number of droplets were observed at X=13∼25 mm from nozzle tip at t=300∼700 μs from injection start. Double-nano spark photography of diesel sprays was carried out and relatively clear double exposure images of droplets were obtained on the same film. Two dimensional size and velocity measurement of droplets were simultaneously carried out based on these photographs. Distribution of droplets velocity was clarified and used to describe the droplets distribution. It was observed that at early period of injection droplets fly away from the spray at a certain angle. However, by time they lose their radial velocity and start to entrain into the spray.</div> <div class="htmlview paragraph">Variation of droplets velocity persuaded the authors to find out a relation between droplets and ambient gas velocity. Ambient gas around the diesel sprays was seeded by light particles and two-dimensional velocity measurement of ambient gas was carried out using a Particle Tracking Velocimetry (PTV) method. Velocity information of droplets and ambient gas was used to clarify the droplets-gas interaction. According to the results, there are two types of ambient gas flow around the diesel sprays. Around the nozzle tip region, ambient gas entrains steeply into sprays, however a vortex of ambient gas was observed around the spray tip. Maximum velocity of ambient gas was very low and about 1/5 of maximum droplet velocities. The velocity of droplets was also much lower than the penetration velocity of spray.</div>

Sprayer applicator-controlled variables, such as nozzle selection and spray volume, will become increasingly important for making labeled POST applications of dicamba in next-generation cropping systems. A field experiment was conducted in 2013 and 2014 at the Northeast Research and Extension Center in Keiser, AR. Tank mixtures of Engenia (a new form of dicamba), glyphosate, glufosinate, andS-metolachlor were applied with TeeJet AIXR, AITTJ60, and TTI nozzles. Two nozzle sizes, 11003 and 11006, were used to vary spray volume from 94 L ha−1to 187 L ha−1, respectively. For barnyardgrass, a significant decrease in control was observed when spray volume was reduced for glyphosate + dicamba in 2013. In 2014, an overall decrease in control was observed for the TTI nozzle when spray volume was reduced to 94 L ha−1, averaged across all herbicide treatments. The addition of the productS-metolachlor to glyphosate + glufosinate + dicamba significantly reduced the droplet spectra for all nozzle types. For example, addingS-metolachlor into the tank-mix decreased the volume median diameter (Dv50) for the TTI nozzle at 187 L ha−1spray volume from 789 μm to 570 μm. The results from this research demonstrate that using low spray volume and coarser nozzles could reduce efficacy of the herbicides on the weed species evaluated. Nozzle selection and spray volume have key roles in maximizing efficacy of POST applications in dicamba-resistant crops. Additionally, evaluating droplet spectra of potential dicamba-containing tank-mixtures is critical for producing the desired droplet size to minimize off-target movement.

A wheel operated boom sprayer working on the principle of eccentric mechanism was evaluated on the independent parameters like nozzle type i.e. flat fan nozzle, hollow cone nozzle and flood jet nozzle in combination with the three different heights of the boom (H1=400 mm, H2=500 mm and H3= 600 mm) and three different type of boom carrying two, three and four nozzles. The dependent parameters studied were nozzle discharge (l h-1), swath width (cm), spray overlap (%), spray coverage (%), size of droplets (µm) and droplet density (droplets/cm2). The study involved the use of dropleaf software, which analysed the spray pattern obtained on water sensitive papers (WSP) used during the study to measure various spraying characteristics of the sprayer. The nozzle discharge (l h-1), swath width (cm) and size of droplets (µm) increased with the increase in the number of nozzles on boom while as the spray overlap (%) and droplet density (droplets cm-2) decreased with an increase in the number of nozzles on boom. The swath width, spray overlap (%) and size of the droplets (µm) increased with an increase in the height of the boom while as nozzle discharge (l h-1), spray coverage (%) and droplet density (droplets cm-2) decreased with the increase in the height of boom.

Advancements in both application hardware (e.g., nozzles and spray assist devices) and spray property modification products have led to a number of products that are specifically designed to maximize the on-target deposition and minimize off-target movement of spray droplets. Testing protocols are being developed to objectively measure spray drift reduction from a wide range of drift reduction technologies (DRTs) including spray nozzles, sprayer modifications, spray delivery assistance, spray property modifiers (adjuvants), and/or landscape modifications. Using a DRT evaluation protocol, the objectives of this work were to study the effects of different air speeds on droplet size from different spray nozzles and spray solutions and to further evaluate the effects of differences in liquid and air temperature on droplet size at the different air speeds tested. Measured spray droplet size was significantly affected by changes in airspeed with the DV0.5 increasing by ∼30–100 μm and the percent of spray volume less than 200 μm decreasing by 50 % or more as the tunnel airspeed was increased from 0.5 to 6.7 m/s (1 to 15 miles per hour), depending on the spray solution, spray nozzle, and air speed. The data also showed a lesser influence of temperature differential between the spray solution and ambient air, with the differences seen most likely resulting from changes in spray solution physical properties with the changes in liquid temperature. Most importantly, this study demonstrated that a reference nozzle evaluated under the same conditions resulted in the reduction in driftable fines while the DRT remained constant across all conditions tested.

When cases of dengue are reported or the density of adult Aedes aegypti (L.) becomes too high, ultralow-volume (ULV) application of insecticides is the recommended control method. The droplet size of an aerosol insecticide influences its efficiency in killing adult mosquitoes. Many studies have been carried out to determine the optimum droplet size that maximises vector control efforts, but only a few have determined droplet-size spectra for specific equipment using different solvents and comparing thermal and non-thermal aerosols. The present study showed that the droplet size for a water-based adulticide-larvicide formulation was larger than for the same formulation diluted in gasoil or biodiesel. No significant differences in adult mortality were observed between sprayers and solvents, but efficacy decreased with distance from the sprayer nozzle. Adult emergence inhibition was more than 90% when using water as a solvent for both thermal and cold foggers, and the efficacy did not decrease with distance from the sprayer nozzle. On the other hand, oil-based solvents became less effective with distance. The use of water as a solvent with both thermal and cold foggers improves the efficacy of the studied formulation containing permethrin as adulticide and pyriproxyfen as larvicide in scaled-up assays. Moreover, it reduces the environmental impact and costs of spraying by comparison with formulations using oil solvents.

A cobertura vegetal que permanece no solo após a colheita beneficia as características físicas e químicas do solo. No entanto, essa palha torna-se uma barreira para a aplicação de herbicidas pré-emergentes, pois impede que eles atinjam o alvo. Nesses casos, a escolha ideal da ponta de pulverização, bem como o tamanho da gota, são imprescindíveis para o sucesso da aplicação. O objetivo deste trabalho foi avaliar a eficiência de transposição do líquido pulverizado, dependente do tamanho de gotas, produzido por vários modelos de ponta de pulverização sobre diferentes densidades de palha de aveia-preta. O trabalho foi realizado em Maringá-PR. Foram utilizadas caixas tipo gerbox como unidades coletoras, cobertas por diferentes quantidades de palha de aveia. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 8 x 7, sendo oito pontas de pulverização (leque e cone) e sete quantidades crescentes de palha de aveia-preta. O produto retido na superfície coletora foi colhido e mediu-se a absorbância. Os dados foram submetidos à análise de variância, e as médias, comparadas entre si por meio do teste de agrupamento Skott-Knott a 5% de probabilidade. Pode-se concluir que o tamanho das gotas é extremamente importante na transposição da palha de aveia. Gotas muito finas e muito grossas não conseguem transpor a barreira formada pela palha de maneira eficiente. Pontas de pulverização que produzem gotas de tamanho médio (CV-IA 02 e ST 02) apresentam volume de transposição maior do que o das demais, sendo recomendadas em aplicações de herbicidas pré-emergentes em plantio-direto até 4 t ha-1 de cobertura morta.

In order to investigate the function expression of droplet size distribution in the spray sheet for agricultural nozzles to improve the pesticide efficacy, some common nozzle types were tested in this study. At present many methods and equipment were used for measuring droplet size. Droplet size is a main parameter influencing the deposition rate and distribution uniformity of pesticide on the target. However, different test results may be caused by different methods or equipment. For selecting a suitable analyzer to test droplet size distribution, three common droplet size analyzers were applied to measure droplet sizes of ST110-03 and ST110-02 nozzles which were standard flat-fan nozzles manufactured by Lechler GmbH. The three analyzers were Particle/Droplet image analysis system, Sympatec HELOS Vario particle size analyzer and Spraytec laser diffraction system and were referred to as PDIA, Sympatec and Spraytec, respectively. Their respective locations were the Institute for Application Techniques in Plant Protection of JKI (Julius Kuhn-Institut), Germany, the Centre for Pesticide Application and Safety of the University of Queensland, Australia, and the Centre for Chemicals Application Technology of China Agricultural University, China. For all the sprays in this study, tap water was sprayed at an operating pressure of 0.3 MPa, and each apparatus was operated complying with its corresponding experimental procedure. For each nozzle type, 3 nozzles were tested with three replications. Results showed that absolute results differed between different tests depending on measuring protocol and type of measuring apparatus, but the nozzle classifications were the same, comparing the results with limits of BCPC nozzle classification obtained by PDIA in JKI. Spraytec was more accessible to authors than other analyzers; therefore, it was selected to study the distribution of droplet size. The volume median diameters (VMDs) of air-induction compact nozzles (IDK), standard flat-fan nozzles (ST) and hollow-cone nozzles (TR), with the orifice sizes of 02 and 03 for each type, were measured at different positions in the spray sheet. The nozzles were all produced by Lechler GmbH in Germany. It was found that the VMD distributions were symmetric for all tested nozzles and the axis of symmetry was the centerline of spray sheet. The VMDs of IDK nozzles were significantly larger than other two types'. The coefficient of variation (CV) of droplet sizes, which were tested at different spray heights but the same horizontal position, indicated that the VMDs of IDK nozzles varied with spray height obviously. Meanwhile, at a fixed spray height, the VMD distribution of IDK along the horizontal direction appeared to be W-shaped; the distributions of ST and TR were parabolas. The parabola opening of ST was larger than that of TR. The tested VMD was then fitted with program code using Matlab software based on least square method. In the fitted VMD distribution equation, independent variables were spray height and horizontal position and dependent variable was VMD. The significant relationship between distribution position and VMD was found, the significance threshold α was set at 0.05. Results also showed that the F-statistic calculated from the data of each nozzle was greater than the critical value of the F-distribution for the desired false-rejection probability of 0.05. The coefficient of determination was greater than 0.8 for all fitted equations. All of these pointed that the obtained equations could describe the droplet size distribution correctly and predicate the size at any position in the spray sheet with precision. The fitted function research involved in this paper will provide the valuable basis to study the VMD distribution of overlapped spray sheet for boom sprayer; the study will improve the uniformity of deposition rate and biological efficacy. Meanwhile, the fine droplet zone in the spray sheet is the target of drift control. Therefore, the VMD distribution is also conducive to the development of novel anti-drift sprayer to reduce the risk of pesticide.

Laser diffraction is among the most widely used methods for spray droplet size measurements. However, the so-called beam-steering effect must be considered when pneumatic atomizers are used for droplet generation. The beam-steering effect is a systematic measurement error, leading to the detection of apparent large spray droplets due to gradients in the refractive index of the gas phase. The established correction method is based on the reduction of the laser diffraction system’s measurement range by deactivation of detectors, relevant for the detection of large droplets. As this method is only applicable when size ranges of real and apparent droplet sizes are clearly different, an alternative method for beam-steering correction is introduced in the presented study. It is based on a multimodal log-normal fit of measured spray droplet sizes. The modality representing the largest droplets is correlated to the beam-steering effect and therefore excluded from the measured size distribution. The new method was successfully applied to previously published droplet size distribution measurements of an internal mixing Air-Core-Liquid-Ring (ACLR) atomizer. In measurements where the method of detector deactivation is applicable, excellent accordance of droplet size distributions, gained by both correction methods, was found. In measurements with overlapping real and apparent parts of the distribution, the new correction method led to a significant reduction of overestimated large droplets. As a consequence, we conclude that the new method presented here for beam-steering correction should be applied in laser diffraction measurements of spray droplet sizes, generated by pneumatic atomizers.

The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade yet not a single technical paper treating the physics and engineering of the fogging process, droplet size measurement, droplet kinetics, or the duct behavior of droplets, from a gas turbine perspective, is available. This paper provides the results of extensive experimental and theoretical studies conducted over several years, coupled with practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines ranging in power from 5 to 250 MW. Part B of the paper treats the practical aspects of fog nozzle droplet sizing, measurement and testing presenting the information from a gas turbine fogging perspective. This paper describes the different measurement techniques available, covers design aspects of nozzles, provides experimental data on different nozzles and provides recommendations for a standardized nozzle testing method for gas turbine inlet air fogging.

<div class="htmlview paragraph">Two factors contribute significantly to the widespread acceptance of a new technology in chemical application 1) simplicity 2) field ruggedness. In the past few years several new types of spray nozzles have been developed to meet the changing needs of applicators. Each is designed to meet specific performance criteria and thus has varying degrees of complexity.</div> <div class="htmlview paragraph">The wide angle full cone spray tip and the extended range flat spray tip are both well suited for uses with sprayer controllers. Each hydraulic spray tip has a wide range of operating pressures. The wide angle full cone tip produces large droplets in a full cone pattern. It is well suited for applications where drift control is essential. The nozzle maintains a 120° spray angle throughout a pressure range of 15 to 40 psi.</div> <div class="htmlview paragraph">The extended range flat spray tip provides excellent spray distribution at both low and high pressures unlike conventional flat spray tips. This allows the operator to tailor his droplet size for his specific application. At lower pressures, systemic herbicides can be applied as larger droplets to minimize drift. At higher pressures, droplet size is decreased and velocity -increased for a thorough, penetrating coverage with contact herbicides.</div> <div class="htmlview paragraph">The third new type of hydraulic spray tip is the twin flat spray. This is designed for post-emergence herbicide applications requiring good penetration and coverage. This spray tip produces smaller droplets than equal size flat spray tips by atomizing the liquid through two orifices. Each forms a flat spray pattern, one directed 30° forward, the other directed 30° to the rear, for better penetration.</div> <div class="htmlview paragraph">Renewed interest in applications using lower carrier volumes has been sparked by the introduction of rotary atomizers. These devices use centrifugal rather than hydraulic energy to form droplets. Advantages include a narrow droplet size range, minimal clogging, and the ability to easily change droplet size. However, acceptance has been limited by mechanical problems, cost and performance limitations.</div> <div class="htmlview paragraph">Air-assisted nozzles have also been developed for low volume applications. These represent a compromise between hydraulic and rotary nozzles. No moving parts, lower cost, versatility and field ruggedness are advantages over rotary atomizers but droplet size control is not as precise.</div>

To accurately measure droplet size using a phase Doppler anemometry (PDA) system, many variables, such as the physical properties of the fuel and optical parameters of the PDA system, should be known, particularly the refractive index of liquid droplets, which is often underestimated. In this study, the effect of a refractive index change on droplet size measurements according to the fuel temperature was experimentally investigated in detail. Light, commercial aviation fuels were used as the working fluids, and a conventional PDA system (DANTEC Co.) was used as the droplet size measuring device. It was confirmed that the change in the refractive index with fuel temperature has a great influence on droplet size measurement. Through extensive experimental investigations, a method for calculating the refractive index according to the fuel temperature change is proposed here.

A newly designed dynamic fluidic sprinkler was tested with different types of nozzles at different operating pressures. Therefore, the aim of this paper was to evaluate the hydraulic performance of a newly designed dynamic fluidic sprinkler. MATLAB R2014a software was employed to establish the computational program for the computed uniformity. Droplet sizes were determined using a Thies Clima Laser Precipitation Monitor. Results showed that the nozzle with a diameter of 5.5 mm gave the highest coefficient of uniformity value of 86% at a low pressure of 150 kPa. The comparison of water distribution profiles for the nozzle sizes (2, 3, 4, 5.5, 6 and 7 mm) at different operating pressures (100, 150, 200, 250 and 300 kPa) showed that a 5.5-mm nozzle size produced a parabola-shaped profile at 150 kPa. The mean droplet diameters for the nozzles sizes of 2, 3, 4, 5.5, 6 and 7 mm ranged from 0 to 4.2, 0 to 3.7, 0 to 3.6, 0 to 3.2, 0 to 0.5 and 0 to 3.8 mm, respectively. The comparison of droplet size distributions showed that 5.5 mm had the optimum droplet diameter of 3.2 mm. The largest droplet sizes had a maximum value of 4.0 for a 2-mm nozzle size. For all the nozzles sizes, 5.5 mm produced better results for hydraulic performance, which can significantly improve the performance and save water for crop production in sprinkler-irrigated fields.