Spray Characteristics Research Articles

Effects of atomizer outlet style on the flow characteristics and dust suppression application

The efficiency of spray dust removal depends significantly on the flow and spray characteristics of the atomizer. This paper established a spray diagnosis system capable of exploring the flow and spray characteristics on the swirl effervescent atomizer. The experimental results indicate that these characteristics were primarily influenced by three key factors: working pressure (Pi), air-liquid mass flow ratio (ALR), and atomizer outlet type. The liquid mass flow rates and spray velocity were increased with Pi and ALR increasing. Conversely, the type of atomizer outlet has minimal impact on the liquid mass flow rate. Increasing the Pi and ALR reduces the spray particle size, boosts droplet velocity, and enhances spray dust removal efficiency. Furthermore, the special-shaped atomizers, square hole and convergent-divergent hole, exhibit favorable spray characteristics and pray dust removal efficiency. Under optimal parameters (Pi=0.6 MPa and ALR =0.18), the square hole of atomizer outlet induces a rapid reduction in the concentration of inhalable dust, achieving a maximum suppression rate of 97.57 %.

Clinically Relevant Characterization and Comparison of Ryaltris and Other Anti-Allergic Nasal Sprays.

The deposition, residence time, and dissolution profile of nasal suspensions containing corticosteroids play a key role in their in vivo efficacy after administration. However, the conventional methods available to characterize nasal products appear to be unsuitable to exhaustively cover these aspects. The work aims to investigate technological aspects of Ryaltris (mometasone furoate and olopatadine hydrochloride nasal spray) compared to other commercial anti-allergic nasal products, namely, Dymista (azelastine hydrochloride and fluticasone propionate), Nasonex (mometasone furoate), and Avamys (fluticasone furoate). Innovative characterization methods were combined with more traditional approaches to investigate the anti-allergic nasal sprays. These methods applied together allowed to differentiate between the different products and provided a clear picture of the nasal product behavior in terms of drug dissolution and deposition. In particular, the dissolution tests were performed exploiting the Respicell® apparatus, an innovative technique that allows for the investigation of inhalation products. Then, formulation viscosities were considered along with a formulation flow test on an inclined plane. Finally, the intranasal deposition profile of the commercial formulations was determined using a silicon nasal cast. The results highlight in vitro significant differences in terms of viscosity as well as dissolution rate of the nasal products, with Ryaltris showing a higher viscosity and lower flow compared to other products, which, along with a corticosteroid faster dissolution rate than Dymista, suggest a potential advantage in terms of clinical behavior.

Optimization Development and Characterization of Film-forming Transdermal Spray

Optimization Development and Characterization of Film-forming Transdermal Spray

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.

Comparison between Liquid Immersion, Laser Diffraction, PDPA, and Shadowgraphy in Assessing Droplet Size from Agricultural Nozzles

Spray droplet diameters play a key role in the field of liquid plant protection product (PPP) application technology. However, the availability of various measurement techniques, each with its unique operating principles for evaluating droplet size spectra, can lead to different interpretations of spray characteristics. Therefore, in this study, four measurement techniques—Liquid Immersion (LI), Laser Diffraction (LD), Phase Doppler Particle Analysis (PDPA), and Shadowgraphy (SG)—were utilized to evaluate the droplet size distribution of agricultural spray nozzles. Additionally, PDPA and SG were used to assess the average velocity of spray droplets. Experiments were conducted in three different laboratories with the main aim of comparing results obtained with various types of equipment utilized under ordinary practical conditions. Spraying tests were carried out using three flat fan nozzles and an air-induction flat fan nozzle. As a general trend, the lowest values for droplet diameters were measured using the Laser Diffraction technique, followed by Shadowgraphy. The PDPA technique provided the highest values for mean diameters (D10, D20, and D30) and the numeric median diameter (Dn0.5), whereas the Liquid Immersion method yielded the highest values for the Sauter mean diameter (D32) and volumetric diameters (Dv0.1, Dv0.5, and Dv0.9). Importantly, all measurement techniques were able to discriminate the four nozzles based on their Dv0.5 diameter. Average droplet velocities showed a similar pattern across the four nozzles with the PDPA and the SG measurement techniques. The differences in diameter values observed with the four measurement techniques underline the necessity of always including reference nozzles in spray quality assessments to base classifications on relative rather than absolute values.

Correlation Between Dynamic Spray Plume and Drug Deposition of Solution-Based Pressurized Metered-Dose Inhalers.

Background: The lack of visual dynamic spray characterization has made the understanding of the physical processes governing atomization and drug particle formation difficult. This study aimed to investigate the changes in the spray plume morphology and aerodynamic particle size of solution-based pressurized metered-dose inhalers (pMDIs) under different conditions to achieve better drug deposition. Methods: Solution-based pMDIs were studied, and the effects of various factors, such as propellant concentration, orifice diameters, and atomization chamber volume, on drug deposition were examined by analyzing the characteristics of spray plume and aerodynamic particle size. Results: Reducing the actuator orifice and spray area led to a concentrated spray plume and increased duration and speed. Moreover, the aerodynamic particle sizes D50 and D90 decreased, whereas D10 remained relatively unchanged. Decreasing the atomization chamber volume of the actuator led to reduced spray area and an increased duration but a decreased plume velocity. D90 exhibited a decreasing trend, whereas D10 and D50 remained relatively unchanged. Reducing the propellant concentration in the prescription, the spray area and the plume velocity first decreased and then increased. The duration initially increased and then decreased. The values of D50 and D90 showed an initial decreasing followed by an increasing trend, whereas D10 remained relatively unchanged. Conclusions: During the development process, attention should be paid to the changes in the spray area, spray angle, duration, and speed of the spray plume. This study recommended analyzing the characteristics of the spray plume and combining the data of two or more aerodynamic particle size detection methods to verify the deposition in vitro to achieve rapid screening and obtain high lung deposition invivo.

Effect Of Wavy Structure Of Liquid Film On Flow Characteristics Of Impingement Jet Flowing On Fuel Liquid Film

In recent years, diesel engines have been downsized in order to improve combustion efficiency by using high-pressure injection to atomize the fuel and to increase fuel economy. As a result, the diesel spray flame inevitably impinges on the combustion chamber wall, resulting in heat loss due to heat transfer between the flame and the wall. According to Newton's cooling law, the heat transferred from the flame to the wall is proportional to the heat transfer coefficient, which is closely related to the flow of the spray flame. However, there are few reports on the flow of a spray flame impinging on a wall. The flow characteristics of a non-vaporized spray impinging on a wall surface, assuming that the flow of a spray flame impinging on a wall surface is equivalent to that of a non-vaporized spray. The fuel film formed on the wall affected on the flow characteristics of the spray. When the spray flame impinges on the wall in the engine cylinder, no liquid film is formed on the wall. Still, during cold start, a liquid fuel film may form on the piston wall due to the low temperature in the engine cylinder, resulting in HC and soot emissions. As a result, the spray may flow over the formed film. Therefore, it is necessary to investigate the flow characteristics of the spray flowing over the fuel film. In this study, the experiments using an impingement gas jet were conducted on a wall surface with a fuel film, and the velocity field of the jet after impingement of the wall surface was measured by the time-series PIV. In addition, the thickness of the wavy liquid film formed by the gas jet impingement was measured by using the laser-induced fluorescence (LIF) method, discussing the relationship between the velocity of the jet after wall impingement and the characteristics of the wavy liquid film.

Numerical study on the effect of high efficient cooling nozzles and varying cooling intensity on metallurgical transport behaviors during the slab continuous casting

In this study, the spray characteristics of the cooling water flux of the traditional single nozzle and novel dual nozzle were innovatively and effectively incorporated into a 3D/2D flow-temperature-concentration segmented model. The model was used to investigate the effects of spray characteristics on the flow, heat distribution, solute transport, solidified shell, and mushy zone of steel in the continuous casting. The results showed that various flow patterns of liquid steel in the turbulent zone significantly affected the temperature and carbon concentration distribution. Until Zone 7, the cooling water fluxes in the six cases remained unchanged. The peak temperatures of cases 1 and 4 in Zone 7 were 1253.11 and 1273.51 K, respectively, indicating that the spray characteristic was the primary cause of the variations in slab surface temperatures. The cooling water fluxes in the six cases change from Zone 8 onward. The six cases had differences of −21.39, 17.87, 46.95, −22.08, 16.86, and 45.68 K between the initial and final temperatures in Zone 8, respectively, meeting the requirement of keeping the maximum temperature recovery rate of slab surface under 100 °C/m. However, the final temperatures for cases 2, 3, and 6 were 1225.62, 1196.50, and 1218.91 K, respectively. These temperatures fall within a realistic plastic temperature range, which must be higher than 1220 K. As a result, the plastic cracking in the slab was possible. The maximum temperature gradient differences of the six cases between feature lines at the end of Zone 8 were 0.793, 0.814, 0.829, 0.185, 0.179, and 0.179 K/mm. These results showed that the optimization effect on the temperature gradient difference was insignificant as the cooling intensity rose. However, the carbon concentration uniformity was marginally improved by increasing the cooling water flux. Finally, a state-owned steel company in China chose case 5 (dual nozzle with moderate cooling intensity at the slab solidified end) as the optimum option for the slab continuous casting caster. The dual nozzle enhanced and promoted the efficient and homogeneous production of the metallurgical process.

Study on the influence of spray characteristics and air flow direction on heat transfer of spray evaporative condenser

Spray cooling is effectively utilized in evaporative condensers to achieve efficient heat and mass transfer transmission, while also effectively preventing performance degradation caused by packing blockage. The heat transfer efficiency is strongly affected by the relative flow direction between the spray and air flow. This work employs computational fluid dynamics to evaluate and examine the heat transfer effects of parallel and countercurrent air and spray flow in evaporative condensers. The findings indicate that increasing spray density and wall temperature enhances heat transfer efficiency. Smaller droplets with lower initial velocity exhibit superior heat transfer capabilities in parallel flow, while smaller droplets also perform well in countercurrent flow as long as the initial velocity is not too high. Additionally, a slight increase in air velocity improves heat transfer efficiency in both parallel and countercurrent flow conditions. It is important to note that the countercurrent condition has a larger heat transfer effect than the parallel flow.

Experimental study on the flash boiling spray characteristics and jet fluctuation of high-pressure direct injection liquid ammonia

The high-temperature environment of actual engines significantly influences the characteristics of high-pressure liquid ammonia flash boiling spray and leads to jet instability. Therefore, this study investigated the influence mechanisms of different ambient temperatures on the high-pressure liquid ammonia flash boiling spray characteristics in a constant volume chamber. Simultaneously, it conducted the first exploration of the fluctuation characteristics of liquid ammonia jets, laying a foundation for achieving the stable and efficient combustion. The results indicate that the spray exhibits a three-stage axial development process at different ambient temperatures and ambient pressures, and the non-dimensional empirical formulas for describing the different stages of ammonia were proposed. In high-temperature conditions, the spray area is subject to the synergistic effects of flash boiling and evaporation. During the early stages, the spray development is dominated by flash boiling, leading to a rapid increase in the change rate of the spray area. However, during the later stages, the spray development is dominated by high-temperature evaporation, resulting in a rapid decrease in the change rate of spray area. Therefore, with increasing ambient temperature, the spray area experiences a significant reduction during the later stages. Through an analysis of spray centroid fluctuations at different ambient temperatures, it is evident that with rising ambient temperature, thermal disturbances intensify, leading to an increase in the oscillations deviation of the near-nozzle local region, and the maximum growth rate reaches 59.16%. Regarding different flash boiling stages, the spray centroid fluctuation is more stable during the transition flash boiling stage, with oscillation deviations below 0.02 at all ambient temperatures.

Effects of dynamic injection pressures on spray, combustion, and exhaust emission characteristics in a CRDI diesel engine with naval vessel fuel

Effects of dynamic injection pressures on spray, combustion, and exhaust emission characteristics in a CRDI diesel engine with naval vessel fuel

Determination of sprayer parameters for fruit nurseries

The paper highlights that in industrial plantings, pests and weeds control is conducted using sprayers. To establish the required liquid fl ow rate, it is necessary to use calculations for sprayer adjustment. A small-sized, remotely controlled «GNOM» unit, developed at Gorsk Agrarian University, is designed for various tasks, including herbicidal spraying in fruit nurseries. (Research purpose) The research aims to substantiate the optimal parameters of the spraying unit in the herbicide treatment module. It also seeks to investigate the dependence of the flow rate of the working fluid and quality of liquid spray on the pressure in the system. (Materials and methods) A laboratory installation was developed to study the spray characteristics. Nylon threads with diameters of 100 and 250 micrometers were placed within the spray zone, and the resulting liquid spray was captured using a Nikon COOLPIX 58100 digital camera. Each subsequent experiment was carried out at a liquid pressure of 0.05 megapascals more than the previous one. (Results and discussion) The experiments resulted in obtaining images of the spray swath for a small-sized self-propelled unit, allowing for the categorization of the spray based on droplet sizes. The theoretical analysis demonstrated how changes in the air volume within the tank influence both the pressure and quality of the liquid spray. Additionally, it showed how the dispersion depends on the pressure of the working fluid. (Conclusions) The analysis of the working fluid spray showed that at a pressure in the hydraulic system in the range from 0.65 to 0.75 megapascals and a spray angle of 90 degrees, the highest quality fine spray is observed, the flow rate of the working fluid is in the range of 0.4-0.6 liters per minute, which very signifi cantly affects the size of the treated area in the direction of its increase at one tank refueling unit.

Investigation of containment spraying characteristics based on the correction of droplet evaporation shielding effects

Historically, the spray models in the accident analysis program are mostly based on the isolated droplet and ignore the shielding effects among droplets, which theoretically introduces some errors. This paper investigates the effect of multi-droplet shielding on spray evaporation by taking the containment spray systems as the research object. By discussing the correction factors, the law of droplet group shielding effects can be studied, and then the correction of the spray package can be realized by the self-programming. After that, the transient response characteristics of temperature and pressure in the containment before and after the model correction are studied by modeling the loss of coolant accident and main steam line break accident, respectively. And, this research tries to analyze the influence of the cell normalization model as well as spray parameters on the calculation results. The results reveal that the program can achieve more accurate prediction after being modified by the shielding effects, and the multi-cell model can capture the temperature stratification effects more accurately under accident conditions. Additionally, the spray temperature and spray sizes have an insignificant effect on the in-shell thermal hydraulics response characteristics, but the increase of the spray flow rate has a better effect on the mitigation of the temperature stratification effects and the suppression of the in-shell pressure. The research in this paper can provide some reference or research ideas for accurate modeling and safety analysis of accidents.

Optimization of Spray Characteristics of Full Cone Nozzles Used in Pesticide Application Using the Taguchi Method

The present study aims to reduce the amount of pesticide that can be released into environment, soil, air, and water by minimizing the type of nozzle and the use of excess pesticides by making use of the Taguchi method. For this purpose, studies were carried out to determine the spray characteristics of the pesticide. The sodium fluorescein was used in the experiments. In this study, the effects of the nozzle-to-surface distance (spray height), spray pressure, nozzle orifice diameter, and nozzle position angle on the droplet diameter and flow characteristics were investigated using the Taguchi method. The mean diameter values were determined first. Then, the volumetric median diameter (VMD) was considered as performance parameter and L9(34) orthogonal sequence was chosen as the experimental plan for four parameters that were determined. Calculating the VMD considered as the performance characteristics, optimum results were obtained using 6 bar spray pressure, 100 mm spray height, 30o nozzle position angle, and 1.10 mm nozzle orifice diameter. The VMD values were calculated using the image processing method and the effects of the parameters on the droplet diameter were interpreted using charts.

The influence of acetylene black microparticles as a fuel additive in pure palm oil and its performance characteristic on diesel engine

Fuel additives are recognized for their potential to make diesel engines cleaner and more efficient. However, the use of Pure Palm Oil (PPaO) as a fuel faces challenges due to its inherent combustion inefficiencies. This study explores how Acetylene Black (AB), as an additive, affects the combustion performance and spray characteristics of a diesel engine. Observations of spray phenomena were conducted using a High-Speed Camera Phantom C110. The addition of AB to PPaO resulted in an increase in engine power and torque by 11.43 % at a 60 % load, averaging a 2.97 % improvement over diesel fuel (DF). PPaO demonstrated the most significant improvement in Specific Fuel Consumption (SFC) by 17.2 % at a 40 % load, averaging an 8.2 % increase. For PPaO with AB (PPaOAB), the greatest enhancement in SFC occurred at a 10 % load, showing a 9.2 % improvement over DF, with an average increase of 2.1 %. The study also found that thermal efficiency was optimally enhanced with PPaOAB at a 20 % load, achieving a remarkable 17.7 % improvement compared to DF. Notably, the inclusion of PPaOAB significantly reduced the thickness of carbon deposits on the pistons and cylinder head by 51.8 % and 3.9 %, respectively, and improved spray angle and penetration compared to PPaO. These findings suggest that AB could be a promising additive for PPaO, sparking further research interest in the application of AB in other fuels.

Advancing Fuel Spray Characterization: A Machine Learning Approach for Directly Injected Gasoline Fuel Sprays

Compression ignition engines when operated on gasoline fuels cause significant reduction in NOx and particulate emissions. In such advanced combustion strategy, the fuel-oxidiser mixing process, intensified by the prolonged ignition delays of gasoline fuels, directly affects the stability and efficiency of combustion. Thus, optimising fuel spray characteristics leads to optimisation of injector design, engine performance and subsequent decrease in emissions. Since spray development is a complex process that involves wide range of length and time scales, computationally expensive modelling techniques can be replaced with machine learning (ML) models. These ML models are employed to predict spray characteristics utilizing datasets generated from comprehensive spray studies. In this work, a dataset of about 5400 instances taken from non-evaporating gasoline fuel spray imaging experiments under Gasoline Compression Injection (GCI) engine conditions is used to train various ML models with data split of 70 % and 30 % for training and testing, respectively, with five-folds cross-validation performed within the training. The fuel injection pressure (60 – 150 MPa), chamber pressure (0.1 – 2 MPa), nozzle diameter, nozzle hole conicity and injection duration are used as input features to the models for predicting the spray tip penetration and spray angle. The performance of four ML models was evaluated and compared under default and tuned hyperparameters against experimental data and available physics-based correlations in the literature. The models include random forest, extreme gradient boosting, multilayer perceptron, and elastic-net. The results show that the hyperparameter-tuned extreme gradient boosting model performs best in predicting the spray parameters. The overall model performance was evaluated using the coefficient of determination (R2), mean absolute error (MAE), and root mean squared error (RMSE), resulting in values of 0.884, 0.651, and 1.571, respectively. This study presents compelling evidence demonstrating the effectiveness of ML as a powerful tool for isolating non-linear behaviors from physical processes. By effectively decoupling these behaviors, ML enhances the accuracy of predicting spray characteristics while significantly reducing computational costs. The application of ML in fuel injector design has the potential to revolutionize engine performance and contribute to substantial reductions in emissions.

Experimental study on spray characteristics of aviation kerosene RP-3 in a radial rotary atomizer

Experimental study on spray characteristics of aviation kerosene RP-3 in a radial rotary atomizer

Investigating Spray Characteristics of Synthetic Fuels: Comparative Analysis with Gasoline

Article Investigating Spray Characteristics of Synthetic Fuels: Comparative Analysis with Gasoline Weidi Huang 1,2, Mitsuharu Oguma 2, Koichi Kinoshita 2, * , Yohko Abe 2, and Kotaro Tanaka 1,3 1 Carbon Recycling Energy Research Centre, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi 316-8511, Japan 2 Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology, Namiki 1-2-1, Tsukuba 305-8564, Japan 3 Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi 316-8511, Japan * Correspondence: koichi-kinoshita@aist.go.jp Received: 13 March 2024; Revised: 22 May 2024; Accepted: 31 May 2024; Published: 5 June 2024 Abstract: Studying synthetic fuels is imperative due to their potential to offer sustainable alternatives to conventional fossil fuels, thereby addressing environmental concerns, enhancing energy security, and facilitating the transition to cleaner and more efficient transportation systems. This study presents an experiment analysis concentrating on spray characteristics of five types of synthetic fuels (bio-naphtha, EtG, G40, bio-ethanol, and DMC) in a comparison with gasoline. The experiment was conducted ranging from non-evaporated conditions to evaporated conditions, to thoroughly assess the spray behavior of the tested fuels. Results showed that EtG and G40 share similar properties with conventional gasoline. The discharge coefficient (Cd) was found to increase closely linearly with the square root of fuel density. Under non-evaporated condition (Ta = 25 °C), except for DMC, the spray tip penetration of other fuels deviates within ±5% compared to gasoline. Under evaporated condition (Ta = 200 °C), EtG maintains a spray tip penetration within ±5% of gasoline, while bio-naphtha, G40, and DMC fall within ±10% of gasoline. Notably, bio-ethanol shows a 12% higher penetration compared to gasoline, likely due to its slower evaporation and higher latent heat of vaporization.

Study on Spray Characteristics and 0-D Model of Marine Injector with Large Orifice Diameter

ABSTRACT Low carbon, cleanliness and efficiency are the three key challenges facing the development of diesel engines. Biodiesel is a crucial step in the transition from fossil fuels to zero-carbon fuels. This study was carried out to investigate the effects of injection pressure and ambient pressure on the biodiesel spray characteristics of a marine large orifice diameter injector. Injection mass has a nonlinear relationship with short injection duration and a linear relationship with long injection duration. Increasing the injection pressure shortens the nonlinear stage and enhances the linear effect. When the injection pressure is increased from 35 MPa to 140 MPa, the injection delay is shortened by 10% (2.5 ms), and the diameter nozzle has almost unaffected on the injection delay. The Arai model was revised based on experimental data to improve its prediction effect on sprays with large nozzle diameters. The new model considers the effects of fuel density and ambient density on penetration before and after breakup, respectively. The penetration of the new model is still proportional to time of after start of injection (t) before the breakup and proportional to t0.6 after the breakup. Increasing the ambient pressure enhances the influence of injection conditions on dimensionless penetration. Compared with the Arai model, the new model reduces the sensitivity of the dimensionless penetration to the injection pressure. Research on biodiesel spray and spray models under large nozzle diameter conditions will be of great help to the application of low-carbon and clean fuels in marine diesel engines.

Microscopic spray characteristics of diethyl ether–diesel blends under single and split injection strategies

The phase doppler interferometry technique was used to thoroughly investigate microscopic spray characteristics of single and split injection strategies. The diethyl ether blending with diesel resulted in smaller and uniform droplet formation. Diethyl ether–diesel blend spray exhibited a lower droplet axial velocity distribution than baseline diesel, which can be improved by split injection strategies. At atmospheric pressure, the maximum axial velocity for diesel and diethyl ether–diesel blends was almost identical under single and split injection strategies. However, split injection improved the spray droplet's axial velocity at higher ambient pressures compared to single injection. The chances of coalescence and having coarse droplets were higher at elevated ambient pressure, especially for lower fuel injection pressures. Therefore, increasing the fuel injection pressure is more suitable to avoid droplet coalescence. Unlike the split ratio, dwell time strongly influenced fuel spray atomization. The droplet diameter distribution exhibited a higher probability of finer droplets for a longer dwell time of 0.45 ms than a shorter dwell time of 0.15 ms. A major finding of this study is that diethyl ether–diesel blend spray with a longer dwell time exhibited superior spray characteristics.