Journal articles: 'Atomization and Sprays'

1

Panão, Miguel. "Ultrasonic Atomization: New Spray Characterization Approaches." Fluids 7, no. 1 (January 7, 2022): 29. http://dx.doi.org/10.3390/fluids7010029.

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In particle engineering, spray drying is an essential technique that depends on producing sprays, ideally made of equal-sized droplets. Ultrasonic sprays appear to be the best option to achieve it, and Faraday waves are the background mechanism of ultrasonic atomization. The characterization of sprays in this atomization strategy is commonly related to the relation between characteristic drop sizes and the capillary length produced by the forcing frequency of wavy patterns on thin liquid films. However, although this atomization approach is practical when the intended outcome is to produce sprays with droplets of the same size, drop sizes are diverse in real applications. Therefore, adequate characterization of drop size is paramount to establishing the relations between empirical approaches proposed in the literature and the outcome of ultrasonic atomization in actual operating conditions. In this sense, this work explores new approaches to spray characterization applied to ultrasonic sprays produced with different solvents. The first two introduced are the role of redundancy in drop size measurements to avoid resolution limitation in the measurement technique and compare using regular versus variable bin widths when building the histograms of drop size. Another spray characterization tool is the Drop Size Diversity to understand the limitations of characterizing ultrasonic sprays solely based on representative diameters or moments of drop size distributions. The results of ultrasonic spray characterization obtained emphasize: the lack of universality in the relation between a characteristic diameter and the capillary length associated with Faraday waves; the variability on drop size induced by both liquid properties and flow rate on the atomization outcome, namely, lower capillary lengths produce smaller droplets but less efficiently; the higher sensibility of the polydispersion and heterogeneity degrees in Drop Size Diversity when using variable bin widths to build the histograms of drop size; the higher drop size diversity for lower flow rates expressed by the presence of multiple clusters of droplets with similar characteristics leading to multimodal drop size distributions; and the gamma and log-normal mathematical probability functions are the ones that best describe the organization of drop size data in ultrasonic sprays.

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2

Arrowsmith, A. "Atomization and Sprays." Chemical Engineering Science 45, no. 5 (1990): 1435. http://dx.doi.org/10.1016/0009-2509(90)87140-n.

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Ding, Hong Yuan, Peng Deng, Xu Yao Mao, and Chao Wu. "Flash Boiling Spray Simulation Based on Void Fraction and Superheat Controlling." Applied Mechanics and Materials 737 (March 2015): 289–95. http://dx.doi.org/10.4028/www.scientific.net/amm.737.289.

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A new flash boiling spray model whose atomization criterion based on the void fraction and superheat while evaporation model based on the dual-zone method is established to simulate the flashing sprays. The model function is implemented in KIVA program. Flash boiling spray model predicts spray penetration and spray cone angle and its development trend, in good agreement with the experimental results. The model has a good capability in simulating flash sprays at low superheat conditions, which breakup is controlled by void fraction, as well as high superheat transition process. It can also predict flare flashing sprays to some extent at higher superheat conditions.

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Prasad, Arvind, and Hani Henein. "Droplet cooling in atomization sprays." Journal of Materials Science 43, no. 17 (September 2008): 5930–41. http://dx.doi.org/10.1007/s10853-008-2860-2.

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Hu, Zuxiang, Benyi Zhang, and Haoqian Chang. "A Study on Dust-Control Technology Used for Large Mining Heights Based on the Optimization Design of a Tracking Spray Nozzle." Atmosphere 14, no. 4 (March 26, 2023): 627. http://dx.doi.org/10.3390/atmos14040627.

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Intense cutting-induced dust production in fully mechanized mining faces (FMMFs) with large mining heights produces a high amount of dust that is difficult to capture and severely affects the working environment, threatening the health of occupational staff. The effective spray range and atomization performance of tracking sprays are counteracted by the influences of the mine’s height and ventilation airflow in FMMFs. Thus, optimizing the spray’s parameters and relationship between the effective spray range and atomization performance to reduce dust levels is the main priority of dust-control techniques. In this study, a new swirl-core atomization nozzle is developed based on fluid mechanics and the solid–liquid coalescence mechanism. The liquid generates a circumferential velocity when passing through the swirl core, which considerably increases the droplet breaking power and reduces the droplet cohesion factor, achieving a remarkable atomization effect. The spray angle of the new nozzle is 57°, which is 80.9% greater than the GZPW-16 mine-use nozzle (31.5°); the effective spray range increases from 5.2 to 5.9 m; and the spray’s mist saturation is significantly better than the GZPW-16 mine-use nozzle. Under different test pressures, the particle size range of the droplets produced by the new nozzle and dust particles on site satisfied the best synergy of droplet–dust coalescence. The total and respirable dust-reduction rates were 78% and 75.1%, respectively, which were 42% and 65% higher than those of the original nozzle. The new nozzle effectively improves the efficiency of the single dust-control technique of the tracking spray, which is significant for the dust-prevention and -control technology of FMMFs with large mining heights.

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Sparacino, Berni, d’Adamo, Krastev, Cavicchi, and Postrioti. "Impact of the Primary Break-Up Strategy on the Morphology of GDI Sprays in 3D-CFD Simulations of Multi-Hole Injectors." Energies 12, no. 15 (July 26, 2019): 2890. http://dx.doi.org/10.3390/en12152890.

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The scientific literature focusing on the numerical simulation of fuel sprays is rich in atomization and secondary break-up models. However, it is well known that the predictive capability of even the most diffused models is affected by the combination of injection parameters and operating conditions, especially backpressure. In this paper, an alternative atomization strategy is proposed for the 3D-Computational Fluid Dynamics (CFD) simulation of Gasoline Direct Injection (GDI) sprays, aiming at extending simulation predictive capabilities over a wider range of operating conditions. In particular, attention is focused on the effects of back pressure, which has a remarkable impact on both the morphology and the sizing of GDI sprays. 3D-CFD Lagrangian simulations of two different multi-hole injectors are presented. The first injector is a 5-hole GDI prototype unit operated at ambient conditions. The second one is the well-known Spray G, characterized by a higher back pressure (up to 0.6 MPa). Numerical results are compared against experiments in terms of liquid penetration and Phase Doppler Anemometry (PDA) data of droplet sizing/velocity and imaging. CFD results are demonstrated to be highly sensitive to spray vessel pressure, mainly because of the atomization strategy. The proposed alternative approach proves to strongly reduce such dependency. Moreover, in order to further validate the alternative primary break-up strategy adopted for the initialization of the droplets, an internal nozzle flow simulation is carried out on the Spray G injector, able to provide information on the characteristic diameter of the liquid column exiting from the nozzle.

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Mohandas, Anu, Hongrong Luo, and Seeram Ramakrishna. "An Overview on Atomization and Its Drug Delivery and Biomedical Applications." Applied Sciences 11, no. 11 (June 2, 2021): 5173. http://dx.doi.org/10.3390/app11115173.

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Atomization is an intricate operation involving unstable and complex networks with rupture and fusion of liquid molecules. There are diverse details that typify the spray formation, which are the technique and configuration of the atomization process, dimension and structure of the nozzle, experimental parameters, etc. Ultimately, the process generates fine sprays from the bulk of a liquid. Some examples of atomization that we come across in our day-to-day life are antiperspirant or hair spray, shower head, garden sprinkler, or cologne mist. In this review paper we are briefly discussing the theoretical steps taking place in an atomization technique. The instabilities of the jet and sheet are explained to understand the underlying theory that breaks the jet or sheet into droplets. Different types of atomization processes based on the energy sources are also summarized to give an idea about the advantages and disadvantages of these techniques. We are also discussing the various biomedical applications of the electrohydrodynamic atomization and its potential to use as a drug delivery system. In short, this paper is trying to demonstrate the diverse applications of atomization to show its potency as a user friendly and cost-effective technique for various purposes.

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Balasubramanyam, M. S., C. P. Chen, and H. P. Trinh. "A New Finite-Conductivity Droplet Evaporation Model Including Liquid Turbulence Effect." Journal of Heat Transfer 129, no. 8 (December 7, 2006): 1082–86. http://dx.doi.org/10.1115/1.2737481.

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A new approach to account for finite thermal conductivity and turbulence effects within atomizing droplets of an evaporating spray is presented in this paper. The model is an extension of the T-blob and T-TAB atomization/spray model of Trinh and Chen [Atomization and Sprays, 16(6), pp. 907–932]. This finite conductivity model is based on the two-temperature film theory in which the turbulence characteristics of the droplet are used to estimate the effective thermal diffusivity for the liquid-side film thickness. Both one-way and two-way coupled calculations were performed to investigate the performance of this model against the published experimental data.

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9

Manna, Lucia, Claudia Carotenuto, Roberto Nigro, Amedeo Lancia, and Francesco Di Natale. "Primary atomization of electrified water sprays." Canadian Journal of Chemical Engineering 95, no. 9 (April 11, 2017): 1781–88. http://dx.doi.org/10.1002/cjce.22841.

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10

Post, Scott L., and Andrew J. Hewitt. "Flat-Fan Spray Atomization Model." Transactions of the ASABE 61, no. 4 (2018): 1249–56. http://dx.doi.org/10.13031/trans.12572.

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Abstract. In pesticide application, the lack of a suitable theoretical atomization model for flat-fan spray nozzles forces a reliance on empirical data and correlations, even for computational simulations. There is considerable difficulty in the theoretical analysis of the liquid sheet emanating from flat-fan nozzles because no simplification to a two-dimensional analysis can be employed, as is done for cylindrical jets. Nonetheless, 50 years ago, Dombrowski and co-workers used linear stability analysis to analyze the breakup of flat-fan spray sheets into ligaments and from ligaments to droplets. Their correlations have not found use because they include parameters that are difficult, if not impossible, to measure. In this work, the Dombrowski model is simplified using dimensional analysis, resulting in a correlation to predict the volume median diameter of flat-fan sprays in terms of common user parameters, i.e., the nozzle size and operating pressure. Keywords: Atomization, Droplet size, Nozzles, Pesticides, Sprayers.

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11

Goodwin, M. S., and G. Wigley. "A Study of Transient Liquid Sheets and Their Relationship to GDI Fuel Sprays(Spray Technologies, Atomization)." Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines 2004.6 (2004): 271–77. http://dx.doi.org/10.1299/jmsesdm.2004.6.271.

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12

Janna, William S. "Research Needs: Industrial Spray Processes, Spray Drying, and Heat Transfer." Applied Mechanics Reviews 41, no. 10 (October 1, 1988): 365–70. http://dx.doi.org/10.1115/1.3151870.

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A survey of researchers and of manufacturers of spraying, drying, and spray heat transfer equipment was conducted. Those that responded provided descriptions of processes and devices that need developmental attention. Several of these problems are described here (eg, a unifying theory of how atomization takes place; a method of evaluating the performance of a spray used to dissolve air in water to enhance mass transfer processes; a comprehensive model for predicting heat transfer from high pressure sprays; etc). It is concluded that many research topics can be gleaned from industry as needs develop and innovative ways are found for sprays to replace conventional methods.

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13

Sphicas, Panos, and Apostolos Pesyridis. "Diesel Spray Liquid Length Imaging at High Pressure." Energies 16, no. 6 (March 20, 2023): 2874. http://dx.doi.org/10.3390/en16062874.

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Engine efficiency and emissions depend on the fuel atomization and dispersion. The fuel atomization and dispersion depend heavily on the ambient pressure and temperature. In this work, to study Diesel sprays in engine conditions, an electrically heated, constant-volume, pressurized vessel was designed and manufactured. The controlling electronics and software were developed and tested to ensure safe and precise operation. A commercial Bosch six-hole automotive Diesel injector was used. The spray spatial and temporal development were studied. In the literature, spray liquid length and cone angle are extensively used to quantify fuel dispersion. In this work, these parameters were quantified using a high-speed shadowgraph technique. Models were derived to describe the temporal evolution of the liquid core. Such models can be used to predict the Diesel spray behaviour and the engine performance.

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14

Jassim, Ahmad K., Basim A. Abd Alhay, Rakad K. Abd Al Kadhim, Fatima Kh Hato, and Dhaa A. Hashim. "A Comparison of Soybean Oil Methyl Ester and Diesel Sprays behavior and atomization characteristics." Journal of Petroleum Research and Studies 7, no. 1 (May 6, 2021): 59–72. http://dx.doi.org/10.52716/jprs.v7i1.162.

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The present numerical study compares between spray characteristics of diesel and soybean oil methyl ester (SME biodiesel) under non-evaporating sprays. The spray structure of diesel and biodiesel fuel (soybean oil) in a common rail injection system are investigated and compared with that of available experimental data used image processing and atomization performance analysis. The proposed approach for the liquid phase based on the statistical properties of sprays be used to describe the liquid and gas phases in an Eulerian-Eulerian approach. The main concept for this model is the possibility of describing a poly disperse spray by using moments of a drop number size distribution function. The main reason for less spray tip penetration in the (SME) comparing with diesel because a larger droplet diameters is the higher density, viscosity and surface tension of (SME). The effect of fuel properties on the near nozzle structure is studied. The comparisons are referring that the spray drag, breakup and collision processes are promoted.

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15

Jasim, Noor Mohsin. "A Comparison of Soybean Oil Methyl Ester and Diesel Sprays Behavior and Atomization Characteristics." Journal of Petroleum Research and Studies 7, no. 4 (May 7, 2021): 65–79. http://dx.doi.org/10.52716/jprs.v7i4.206.

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The present numerical study compares between spray characteristics of diesel and soybean oil methyl ester (SME biodiesel) under non-evaporating sprays. The spray structure of diesel and biodiesel fuel (soybean oil) in a common rail injection system are investigated and compared with that of available experimental data used image processing and atomization performance analysis. The proposed approach for the liquid phase, which based on the sprays’ statistical properties, is used to present the gas and liquid phases in an Eulerian-Eulerian approach. The main concept for this model is the possibility of describing a poly disperses spray by using moments of a drop number size distribution function. The main reason for less spray tip penetration in the (SME) comparing with diesel because a larger droplet diameters is the higher density, surface tension and viscosity of (SME). The fuel properties effect on the near nozzle structure is studied. The comparisons are referring that the spray drag, breakup and collision processes are promoted.

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16

Lozano, A., H. Amaveda, F. Barreras, X. Jorda`, and M. Lozano. "High-Frequency Ultrasonic Atomization With Pulsed Excitation." Journal of Fluids Engineering 125, no. 6 (November 1, 2003): 941–45. http://dx.doi.org/10.1115/1.1603301.

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Ultrasonic atomization is a very convenient method to produce sprays of very small droplets. Resulting droplet size distributions are very narrow and the mean diameter is essentially only controlled by the excitation frequency. Generation of droplets in the micron range requires MHz waves, with voltages around 30 V, which translates into power requirements on the order of 10 W. Tunable wave generators with these characteristics are somewhat uncommon. To explore the capabilities of ultrasonic atomization for inhalation therapies, an excitation source, described in this paper, has been designed. The characteristics of the sprays obtained when driving with it a piezoceramic disk are analyzed.

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17

Zhang, Yuyin, Shiyan Li, Wenyuan Qi, and Keiya Nishida. "Evaporation characterization of fuel spray impinging on a flat wall by laser-based measurement." International Journal of Engine Research 18, no. 8 (September 30, 2016): 776–84. http://dx.doi.org/10.1177/1468087416671479.

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It is of interest for engine combustion modeling to quantify the evaporation behaviors of fuel spray impinging on a wall as the fuel atomization, evaporation, and mixing with oxygen in the combustion chamber usually dominate the subsequent combustion processes. In this study, the vapor and liquid mass distributions in diesel-like fuel sprays were quantified using the ultraviolet-visible laser absorption scattering imaging technique. The sprays were injected from a single-hole nozzle with a common-rail injection system and impinged on a flat wall at an ambient pressure of 4 MPa and an ambient temperature of 833 K. The mass of the total fuel vapor, the spray volume covered by the vapor phase, and the air mass entrained into the spray were characterized. The results indicate that the time evolution of these parameters until shortly after the end of injection can be expressed by a power-law function, Yi = ki· ts1.5, where Yi represents the parameter like vapor mass and so on, ts is the time after start of injection, and ki is the coefficient corresponding to Yi. The physics behind this power-law function was analyzed and discussed based on the theory of atomization and evaporation, and verified using measurement data obtained under different conditions of injection quantity.

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Ghaffar, Zulkifli Abdul, Ahmad Hussein Abdul Hamid, and Mohd Syazwan Firdaus Mat Rashid. "Spray Characteristics of Swirl Effervescent Injector in Rocket Application: A Review." Applied Mechanics and Materials 225 (November 2012): 423–28. http://dx.doi.org/10.4028/www.scientific.net/amm.225.423.

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Injector is one of the vital devices in liquid rocket engine (LRE) as small changes in its configurations and design can result in significantly different LRE performance. Characteristics of spray such as spray cone angle, breakup length and Sauter mean diameter (SMD) are examples of crucial parameters that play the important role in the performance of liquid propellant rocket engine. Wider spray cone angle is beneficial for widespread of fuel in the combustion chamber for fast quiet ignition and a shorter breakup length provides shorter combustion chamber to be utilized and small SMD will result in fast and clean combustion. There are several mechanisms of liquid atomization such as swirling, e.g. jet swirl atomization or introducing bubbles into the liquid and effervescent atomization. Introducing a swirl component in the flow can enhance the propellant atomization and mixing whereas introducing bubbling gas directly into the liquid stream inside the injector leads to finer sprays even at lower injection pressures. This paper reviews the influence of both operating conditions and injector internal geometries towards the spray characteristics of swirl effervescent injectors. Operating conditions reviewed are injection pressure and gas-to-liquid ratio (GLR), while the injector internal geometries reviewed are limited to swirler geometry, mixing chamber diameter (dc), mixing chamber length (lc), aeration hole diameter (da), discharge orifice diameter (do) and discharge orifice length (lo).

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Bianchi, G. M., P. Pelloni, F. E. Corcione, L. Allocca, and F. Luppino. "Modeling Atomization of High-Pressure Diesel Sprays." Journal of Engineering for Gas Turbines and Power 123, no. 2 (December 7, 2000): 419–27. http://dx.doi.org/10.1115/1.1361110.

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This paper deals with a numerical and experimental characterization of a high-pressure diesel spray injected by a common-rail injection system. The experiments considered a free non-evaporating spray and they were performed in a vessel reproducing the practical density that characterizes a D.I. diesel engine at injection time. The fuel was supplied at high pressure by a common-rail injection system with a single hole tip. The computations have been carried out by using both the TAB model and a hybrid model that allows one to describe both liquid jet atomization and droplet breakup. In order to validate the breakup model, an extensive comparison between data and numerical predictions has been carried out in terms of spray penetration, Sauter mean diameter, near and far spray cone angles, and spray structure.

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20

ZENG, YANGBING, and CHIA-FON F. LEE. "AN ATOMIZATION MODEL FOR FLASH BOILING SPRAYS." Combustion Science and Technology 169, no. 1 (August 2001): 45–67. http://dx.doi.org/10.1080/00102200108907839.

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21

Raghu, P., N. Nallusamy, and Pitchandi Kasivisvanathan. "Spray Characteristics of Diesel and Biodiesel Fuels for Various Injection Timings under Non Evaporating Conditions." Applied Mechanics and Materials 787 (August 2015): 682–86. http://dx.doi.org/10.4028/www.scientific.net/amm.787.682.

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Fuel spray and atomization characteristics play a vital role in the performance of internal combustion engines. Petroleum fuels are expected to be depleted within a few decades, finding alternative fuels that are economically viable to replace the petroleum fuel has attracted much research attention. In this work spray characteristics such as spray tip penetration, spray cone angle and spray area were investigated for Karanja oil methyl ester (KOME), Jatropha oil methyl ester (JOME) and diesel fuel. The KOME and JOME sprays were characterized and compared with diesel sprays at different injection timings. The macroscopic spray properties were acquired from the images captured by a high speed video camera employing shadowgraphic and image processing techniques in a spray chamber. The experimental results showed that biodiesel fuels had different features compared with diesel fuel after start of injection (ASOI). Longer spray tip penetration, larger spray area and smaller spray cone angle were observed for biodiesel (JOME, KOME) due to its higher density and viscosity than that of diesel fuel.

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22

Ding, Jia-Wei, Guo-Xiu Li, Yu-Song Yu, and Hong-Meng Li. "Numerical Investigation on Primary Atomization Mechanism of Hollow Cone Swirling Sprays." International Journal of Rotating Machinery 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/1201497.

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The atomization process of swirling sprays in gas turbine engines has been investigated using a LES-VOF model. With fine grid resolution, the ligament and droplet formation processes are captured in detail. The spray structure of fully developed sprays and the flow field are observed firstly. A central recirculation zone is generated inside the hollow cone section due to the entrainment of air by the liquid sheet and strong turbulent structures promote the breakup of ligaments. At the exit of injector nozzle, surface instability occurs due to disturbance factors. Axial and transverse mode instabilities produce a net-like structure ligament zone. Finally, the generation mechanism of the droplet is analyzed. It is found that the breakup mechanism of ligaments is located at the Raleigh capillary region. Axial symmetry oscillation occurs due to the surface tension force and the capillary waves pinch off from the neck of the ligaments. Secondary breakup and coalescence occur at the “droplet zone,” resulting in a wider distribution curve at the downstream area.

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FAN, XIAOFENG, and JIANGFENG WANG. "A MARKER-BASED EULERIAN-LAGRANGIAN METHOD FOR MULTIPHASE FLOW WITH SUPERSONIC COMBUSTION APPLICATIONS." International Journal of Modern Physics: Conference Series 42 (January 2016): 1660159. http://dx.doi.org/10.1142/s2010194516601599.

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The atomization of liquid fuel is a kind of intricate dynamic process from continuous phase to discrete phase. Procedures of fuel spray in supersonic flow are modeled with an Eulerian-Lagrangian computational fluid dynamics methodology. The method combines two distinct techniques and develops an integrated numerical simulation method to simulate the atomization processes. The traditional finite volume method based on stationary (Eulerian) Cartesian grid is used to resolve the flow field, and multi-component Navier-Stokes equations are adopted in present work, with accounting for the mass exchange and heat transfer occupied by vaporization process. The marker-based moving (Lagrangian) grid is utilized to depict the behavior of atomized liquid sprays injected into a gaseous environment, and discrete droplet model 13 is adopted. To verify the current approach, the proposed method is applied to simulate processes of liquid atomization in supersonic cross flow. Three classic breakup models, TAB model, wave model and K-H/R-T hybrid model, are discussed. The numerical results are compared with multiple perspectives quantitatively, including spray penetration height and droplet size distribution. In addition, the complex flow field structures induced by the presence of liquid spray are illustrated and discussed. It is validated that the maker-based Eulerian-Lagrangian method is effective and reliable.

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Shrimpton, John S. "ATOMIZATION, COMBUSTION, AND CONTROL OF CHARGED HYDROCARBON SPRAYS." Atomization and Sprays 11, no. 4 (2001): 365–96. http://dx.doi.org/10.1615/atomizspr.v11.i4.50.

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Ren, Ning, A. Blum, C. Do, and A. W. Marshall. "ATOMIZATION AND DISPERSION MEASUREMENTS IN FIRE SPRINKLER SPRAYS." Atomization and Sprays 19, no. 12 (2009): 1125–36. http://dx.doi.org/10.1615/atomizspr.v19.i12.30.

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Jayaraman, Natesa I., and Robert A. Jankowski. "Atomization of Water Sprays for Quartz Dust Control." Applied Industrial Hygiene 3, no. 12 (December 1988): 327–31. http://dx.doi.org/10.1080/08828032.1988.10390341.

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Childs, Robert E., and Nagi N. Mansour. "Simulation of fundamental atomization mechanisms in fuel sprays." Journal of Propulsion and Power 5, no. 6 (November 1989): 641–49. http://dx.doi.org/10.2514/3.23201.

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Faeth, G. M. "Structure and atomization properties of dense turbulent sprays." Symposium (International) on Combustion 23, no. 1 (January 1991): 1345–52. http://dx.doi.org/10.1016/s0082-0784(06)80399-1.

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Shinjo, Junji. "Recent Advances in Computational Modeling of Primary Atomization of Liquid Fuel Sprays." Energies 11, no. 11 (November 1, 2018): 2971. http://dx.doi.org/10.3390/en11112971.

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Recent advances in modeling primary atomization in order to enable accurate practical-scale jet spray simulation are reviewed. Since the Eulerian–Lagrangian method is most widely used in academic studies and industrial applications, in which the continuous gas phase is treated in the Eulerian manner and droplets are calculated as Lagrangian point particles, the main focus is placed on improvement within this framework, especially focusing on primary atomization where modeling is the weakest. First, limitations of the conventional methods are described and then novel modeling proposals intended to tackle these issues are covered. These new modeling proposals include the Eulerian surface density approach, and the hybrid Eulerian surface/Lagrangian subgrid droplet generation approach. Compared to conventional simple yet sometimes non-physical models, recent models try to include more physical findings in primary atomization which have been obtained through experiments or direct numerical simulation (DNS). Model accuracy ranges from one that still needs some adjustment using experimental or DNS data to one which is totally self-closed so that no parameter tuning is necessary. These models have the potential to overcome the long-recognized bottleneck in primary atomization modeling and thus to improve the accuracy of whole spray simulation, and may greatly help to improve the spray design for higher combustion efficiency.

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Kim, Kihyun, and Ocktaeck Lim. "Investigation of the Spray Development Process of Gasoline-Biodiesel Blended Fuel Sprays in a Constant Volume Chamber." Energies 13, no. 18 (September 15, 2020): 4819. http://dx.doi.org/10.3390/en13184819.

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This study investigated gasoline–biodiesel blended fuel (GB) subjected to a fuel spray development process on macroscopic and microscopic scales. The four tested fuels were neat gasoline and gasoline containing biodiesel (5%, 20%, and 40% by volume) at three different ratios. The initial spray near the nozzle revealed that the spray penetration and spray tip velocity both decreased with decreasing biodiesel blending ratio. In addition, the different spray tip velocities at the start of spraying result in different atomization regimes between the fuels. The GB fuels with a low biodiesel blending ratio were disadvantaged in terms of spray atomization due to their lower spray penetration and tip velocity. The macroscopic spray penetration changes were similar to those observed in the microscopic spray. The fuel with the lower biodiesel blending ratio had a larger spray cone angle, indicating increased radial spray dispersion.

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31

Chang, H., D. Nelson, C. Sipperley, and C. Edwards. "Development of a Temporally Modulated Fuel Injector With Controlled Spray Dynamics." Journal of Engineering for Gas Turbines and Power 125, no. 1 (December 27, 2002): 284–91. http://dx.doi.org/10.1115/1.1496118.

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It is now well established that combustion instability in liquid-fueled gas turbines can be controlled through the use of active fuel modulation. What is less clear is the mechanism by which this is achieved. This results from the fact that in most fuel modulation strategies not only is the instantaneous mass flow rate of fuel affected but so too are the parameters which define the post-atomization spray that takes part in the combustion. Specifically, experience with piezoelectric modulated sprays has shown that drop size, velocity, cone angle, and patternation are all affected by the modulation process. This inability to decouple changes in the fueling rate from changes in the spray distribution makes understanding of the mechanism of instability control problematic. This paper presents the results of an effort to develop an injector which can provide temporal modulation of the fuel flow rate but without concomitant changes in spray dynamics. This is achieved using an atomization strategy which is insensitive to both fuel flow rate and combustor acoustics (an over-pressured spill-return nozzle) coupled with an actuator with flat frequency response (a low-mass voice coil). The design and development of the actuator (and its control system) are described, and a combination of phase-Doppler interferometry and imaging are used to establish its performance. Results show that the system is capable of producing sprays which have little variation in cone angle or spray distribution function despite variations in mass flow rate (number density) of greater than 50% over a range of frequencies of interest for control of combustion instability (10 Hz to 1 kHz).

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Kihm, Kenneth D., G. M. Lyn, and S. Y. Son. "ATOMIZATION OF CROSS-INJECTING SPRAYS INTO CONVECTIVE AIR STREAM." Atomization and Sprays 5, no. 4-5 (1995): 417–33. http://dx.doi.org/10.1615/atomizspr.v5.i45.40.

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33

Zhao, Fu-Quan, Amer Ahmad Amer, and John L. Dressler. "ATOMIZATION CHARACTERISTICS OF PRESSURE-MODULATED AUTOMOTIVE PORT INJECTOR SPRAYS." Atomization and Sprays 6, no. 4 (1996): 461–83. http://dx.doi.org/10.1615/atomizspr.v6.i4.50.

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Yamane, Yoshiyuki, Haruyuki Yokota, and Takeyuki Kamimoto. "Atomization and Air-Entrainment Characteristics of Unsteady Dense Sprays." JSME International Journal Series B 37, no. 3 (1994): 604–10. http://dx.doi.org/10.1299/jsmeb.37.604.

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DESANTES, JOSÉ M., SERGIO HOYAS, ANTONIO GIL, KHUONG ANH DUNG, and FRÉDÉRIC RAVET. "A RECENT EULERIAN–LAGRANGIAN CFD METHODOLOGY FOR MODELING DIRECT INJECTION DIESEL SPRAYS." International Journal of Computational Methods 11, no. 03 (June 2014): 1343012. http://dx.doi.org/10.1142/s0219876213430123.

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The global objective of this work is to show the capabilities of the Eulerian–Lagrangian spray atomization (ELSA) model for the simulation of Diesel sprays in cold starting conditions. Our main topic is to focus in the analysis of spray formation and its evolution at low temperature 255 K (-18°C) and nonevaporative conditions. Spray behavior and several macroscopic properties, included the liquid spray penetration, and cone angle are also characterized. This study has been carried out using different ambient temperature and chamber pressure conditions. Additionally, the variations of several technical quantities, as the area coefficient and effective diameter are also studied. The results are compared with the latest experimental results in this field obtained in our institute. In the meantime, we also compare with the normal ambient temperature at 298 K (25°C) where the numerical validation of the model has shown a good agreement.

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SNYDER, HERMAN E., and ROLF D. REITZ. "Direct droplet production from a liquid film: a new gas-assisted atomization mechanism." Journal of Fluid Mechanics 375 (November 25, 1998): 363–81. http://dx.doi.org/10.1017/s0022112098002997.

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X-ray lithography and micro-machining have been used to study gas-assisted liquid atomization in which a liquid film was impinged by a large number of sonic micro-gas jets. Three distinct breakup regimes were demonstrated. Two of these regimes share characteristics with previously observed atomization processes: a bubble bursting at a free surface (Newitt et al. 1954; Boulton-Stone & Blake 1993) and liquid sheet disintegration in a high gas/liquid relative velocity environment (Dombrowski & Johns 1963). The present work shows that suitable control of the gas/liquid interface creates a third regime, a new primary atomization mechanism, in which single liquid droplets are ejected directly from the liquid film without experiencing an intermediate ligament formation stage. The interaction produces a stretched liquid sheet directly above each gas orifice. This effectively pre-films the liquid prior to its breakup. Following this, surface tension contracts the stretched film of liquid into a sphere which subsequently detaches from the liquid sheet and is entrained by the gas jet that momentarily pierces the film. After droplet ejection, the stretched liquid film collapses, covering the gas orifice, and the process repeats. This new mechanism is capable of the efficient creation of finely atomized sprays at low droplet ejection velocities (e.g. 20 μm Sauter mean diameter methanol sprays using air at 239 kPa, with air-to-liquid mass ratios below 1.0, and droplet velocities lower than 2.0 m s−1). Independent control of the gas and the liquid flows allows the droplet creation process to be effectively de-coupled from the initial droplet momentum, a characteristic not observed with standard gas-assisted atomization mechanisms.

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Rashid, Mohd Syazwan Firdaus Mat, Ahmad Hussein Abdul Hamid, Chee Sheng Ow, and Zulkifli Abdul Ghaffar. "An Experimental Investigation on the Effect of Various Swirl Atomizer Orifice Geometries on the Air Core Diameter." Applied Mechanics and Materials 225 (November 2012): 32–37. http://dx.doi.org/10.4028/www.scientific.net/amm.225.32.

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Liquid atomization is a process of changing the liquid into small droplets. There are many applications which are related to liquid atomization including fuel injection in combustion systems and also in agricultural sprays. In pressure swirl atomizer, the liquid is injected into the atomizer through tangential port and a swirling motion is formed inside the swirl chamber. In high strength of swirling motion, an air core will be visible inside the atomizer. The liquid is then discharged from the orifice to form a spray which breaks up the liquid into small droplets. The objective of this research is to investigate the effect of various orifice geometries on the air core diameter. The injection pressure was varied in the range of 2 to 8 bar and water was used as the working fluid. Experiment data shows that the air core diameter increases as the injection pressure increased, regardless the discharge orifice diameter and discharge orifice length. It also found that the air core diameter increases as the discharge orifice length decreases and the discharge orifice diameter increases.

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Kihm, Kenneth D., B. H. Kim, and A. R. McFarland. "ATOMIZATION, CHARGE, AND DEPOSITION CHARACTERISTICS OF BIPOLARLY CHARGED AIRCRAFT SPRAYS." Atomization and Sprays 2, no. 4 (1992): 463–81. http://dx.doi.org/10.1615/atomizspr.v2.i4.60.

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Han, Zhiyu, Scott Parrish, Patrick V. Farrell, and Rolf D. Reitz. "MODELING ATOMIZATION PROCESSES OF PRESSURE-SWIRL HOLLOW-CONE FUEL SPRAYS." Atomization and Sprays 7, no. 6 (1997): 663–84. http://dx.doi.org/10.1615/atomizspr.v7.i6.70.

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Liu, Yumin, Takuji Ishiyama, Kei Miwa, Tomohiro Okubo, and Seiji Miyashiro. "Initial Breakup and Atomization of Droplets in Diesel Fuel Sprays." Transactions of the Japan Society of Mechanical Engineers Series B 61, no. 587 (1995): 2731–37. http://dx.doi.org/10.1299/kikaib.61.2731.

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GOMEZ, ALESSANDRO, and GUNG CHEN. "Charge-Induced Secondary Atomization in Diffusion Flames of Electrostatic Sprays." Combustion Science and Technology 96, no. 1-3 (January 1994): 47–59. http://dx.doi.org/10.1080/00102209408935346.

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Wang, Shilin, Xue Li, Aijun Zeng, Jianli Song, Tao Xu, Xiaolan Lv, and Xiongkui He. "Effects of Adjuvants on Spraying Characteristics and Control Efficacy in Unmanned Aerial Application." Agriculture 12, no. 2 (January 20, 2022): 138. http://dx.doi.org/10.3390/agriculture12020138.

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Pesticide application by unmanned agricultural aerial vehicles (UAVs) has rapidly developed in China and other Asian counties. Currently, tank-mix spray adjuvants are usually added into pesticide solutions to reduce spray drift and facilitate droplet deposition and control efficacy. The currently used tank-mix adjuvants are all derived from conventional ground sprays, and their mechanisms of action in aerial applications are still unclear. In order to clarify the spraying characteristics and control efficacy of those adjuvants in aerial sprays, the performances of various types of tank-mix adjuvants were compared by analyzing droplet spectrum, drift potential index (DIX) in a wind tunnel, field deposition and control efficacy on wheat rust and aphids. The atomization results showed that the addition of adjuvants could change the droplet spectrum of liquid, and the results suggest that droplet size is an effective indicator of spray drift potential. In the field application, the meteorological conditions are complex and uncontrollable, and the effects of adjuvants on droplet deposition and distribution were not significant. Compared with the control solution, there was no significant difference in the deposition amount of each adjuvant solution, and the CVs of deposition were higher than 30%. Adding adjuvants to the spray solution can significantly improve the control efficacy of pesticides on wheat aphids and rust and also prolong the duration of the pesticide. Our results suggest that tank-mix adjuvants should be added when UAVs are used for aerial application. This study can be used as a reference to the research and development or selection of adjuvants in aerial sprays of UAVs.

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Mlkvik, Marek, Róbert Olšiak, and Marek Smolar. "Comparison of the Viscous Liquids Spraying by the OIG and the Oil Configurations of an Effervescent Atomizer at Low Inlet Pressures." Strojnícky casopis – Journal of Mechanical Engineering 66, no. 1 (July 1, 2016): 53–64. http://dx.doi.org/10.1515/scjme-2016-0011.

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AbstractIn this work we studied the influence of the fluid injection configuration (OIG: outside-in-gas, OIL: outside-in-liquid) on the internal flows and external sprays parameters. We sprayed the viscous aqueous maltodextrin solutions (μ = 60 mPa·s) at a constant inlet pressure of the gas and the gas to the liquid mass flow ratio (GLR) within the range 2.5 to 20%. We found that the fluids injection has a crucial influence on the internal flows. The internal flows patterns for the OIG atomizer were the slug flows, the internal flow of the OIL device was annular which led to the significant improvement of the spray quality: Smaller droplets, faster atomization, fewer pulsations.

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Stężycki, P., M. Kowalski, A. Jankowski, and Z. Sławinski. "Laser Research of the Fuel Atomization Process of Internal Combustion Engines." Science & Technique 19, no. 1 (February 5, 2020): 34–42. http://dx.doi.org/10.21122/2227-1031-2020-19-1-34-42.

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The paper presents test methods (mechanical, electrical and optical) for the fuel spray research in combustion engines. Optical methods, imaging and non-imaging can be used in laboratory and engine tests. Imaging methods include flash photography and holography. Their use is limited to testing droplet dimensions larger than 5 µm. Imaging methods have an advantage over non-imaging ones because they allow the droplet to be seen at the point and time where its measurement is required. Non-imaging methods can be divided into two groups: the first, which counts and measures, individual droplets one at a time, and the second, which measures a large number of droplets simultaneously. Exemplary results of research of droplet size distribution in fuel sprays are shown. In tests of atomized fuel spray, in conditions reflecting the conditions of the internal combustion engine, the size of droplets, their distribution in the spray and the velocity of individual droplets are presented. To determine the quality of the fuel spray, two substitute diameters Sauter (D32) and Herdan (D43) were selected, the first of which refers to heat transfer and the second to combustion processes. Laser research equipment including Particle Image Velocimetry laser equipment (PIV), Laser Doppler Velocimeter (LDV) and Phase Doppler Particle Analyzer (PDPA) were applied for testing fuel spray distribution for two kind of fuel. The atomization process from the point of view of combustion and ignition processes, as well as emission levels, is characterized by the best substitute diameter D43, which value is close to the median volume. The most harmful droplets of fuel in the spray are large droplets. Even a few such droplets significantly change the combustion process and emission of toxic exhaust components, mainly NOx.

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Iyer, Venkatraman, and John Abraham. "An Evaluation of a Two-Fluid Eulerian-Liquid Eulerian-Gas Model for Diesel Sprays." Journal of Fluids Engineering 125, no. 4 (July 1, 2003): 660–69. http://dx.doi.org/10.1115/1.1593708.

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A two fluid Eulerian-liquid Eulerian-gas (ELEG) model for diesel sprays is developed. It is employed to carry out computations for diesel sprays under a wide range of ambient and injection conditions. Computed and measured results are compared to assess the accuracy of the model in the far field, i.e., at axial distances greater than 300 orifice diameters, and in the near field, i.e., at axial distances less than 100 orifice diameters. In the far field, the comparisons are of drop mean velocities and drop fluctuation velocities and in the near field they are of entrainment velocities and entrainment constants. Adequate agreement is obtained quantitatively, within 30 percent, and qualitatively as parameters are changed. Unlike in traditional Lagrangian-drop Eulerian-fluid (LDEF) approaches that are employed for diesel spray computations, adequate resolution can be employed in the near field to achieve numerical grid independence when the two-fluid model is employed. A major source of uncertainty in the near field is in the modeling of liquid jet breakup and atomization.

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Gilmore, Paul, Vishnu-Baba Sundaresan, Jeremy Seidt, and Jarrod Smith. "Design and analysis of a synthetic jet actuator-based fluid atomization device." Journal of Intelligent Material Systems and Structures 28, no. 17 (January 30, 2017): 2307–16. http://dx.doi.org/10.1177/1045389x17689938.

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High-pressure nozzles and ultrasonic atomizers are the two most common devices used to generate sprays. Each of these has some disadvantages, such as controllability in high-pressure nozzles and fluid management challenges in ultrasonic devices. To overcome these limitations, a new atomization technology using a synthetic jet actuator was developed and is presented here. The work includes design and experimental analysis of both the stand-alone synthetic jet actuator and the synthetic jet-based atomization device. The synthetic jet actuator is designed using a model-based approach and characterized by measuring dynamic orifice pressure, diaphragm peak-to-peak displacement, flow rate, and power consumption. Orifice pressure reaches 296 Pa at a flow rate of 16 mL/s and 186 Pa at a flow rate of 37 mL/s for two possible synthetic jet actuator geometries, respectively. Piezoelectric diaphragm displacement reaches 50 µm with a brass substrate thickness of 0.20 mm. The synthetic jet-based atomization device is characterized with high-speed imaging and measurement of water atomization rate. It produces droplets with average sizes of 92–116 µm at maximum rates of 19–28 µL/s, depending on the geometry of the synthetic jet actuator. The outcomes of this work are principles for designing effective synthetic jet-based atomization devices, as well as system-level implementation concepts and control schemes.

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Baik, S., J. P. Blanchard, and M. L. Corradini. "Development of Micro-Diesel Injector Nozzles via Microelectromechanical Systems Technology and Effects on Spray Characteristics." Journal of Engineering for Gas Turbines and Power 125, no. 2 (April 1, 2003): 427–34. http://dx.doi.org/10.1115/1.1559901.

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Micromachined planar orifice nozzles have been developed using MEMS (micro-electro-mechanical systems) technology and tested with commercially produced diesel injection systems. Such a system, properly designed, may have the capability to improve the spray characteristics in DI diesel engines due to improved atomization and fuel-air mixing. To demonstrate this process, 14 microplanar orifice nozzles were fabricated with deep X-ray lithography and electroplating (LIGA) technology. The circular orifice diameters were varied from 40 to 260 microns and the number of orifices varied from one to 169. Three plates with noncircular orifices were also fabricated to examine the effect of orifice shape on spray characteristics. These nozzles were then attached to commercial diesel injectors and the associated injection systems were used in the study of drop sizes. The experiments were carried out at two different injection pressures (around 25 MPa and 80 MPa). Local drop sizes were measured by a laser diffraction technique, and the average drop sizes of the whole sprays were measured by a light extinction technique. The drop sizes were found to depend primarily on the total mass flow area. Coalescence droplet collisions among adjacent sprays were apparent for the multiple orifice nozzles. Nonplanar configurations are under development and may show improved performance.

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YAMANE, Yoshiyuki, Haruyuki YOKOTA, and Takeyuki KAMIMOTO. "Study of Atomization and Air-Entrainment Characteristics of Unsteady Dense Sprays." Transactions of the Japan Society of Mechanical Engineers Series B 58, no. 550 (1992): 1955–60. http://dx.doi.org/10.1299/kikaib.58.1955.

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Shinjo, J., and A. Umemura. "Surface instability and primary atomization characteristics of straight liquid jet sprays." International Journal of Multiphase Flow 37, no. 10 (December 2011): 1294–304. http://dx.doi.org/10.1016/j.ijmultiphaseflow.2011.08.002.

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Shriram Sathishkumar, Bommisetty Sambasiva Rao, Sidharth Pradeep, Solai Sairam R. M., Balaji Kalaiarasu, and Prabhu Selvaraj. "Modelling and Validating the Spray Characteristics of a Co-axial Twin-Fluid Atomizer Using OpenFOAM." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 91, no. 1 (January 17, 2022): 35–45. http://dx.doi.org/10.37934/arfmts.91.1.3545.

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Today, the applications of sprays cover a wide range of fields. Their role in internal combustion engines is instrumental in maintaining higher engine efficiency. A deeper understanding of the liquid-gas phase interaction in sprays is crucial to the atomization process. The methods and models used in the simulations have their challenges due to the various discretization schemes and solutions used. To develop and validate the computational models, well defined experimental data is required. In the present work, spray characteristics were studied numerically through OpenFOAM. As the spray characteristics are closely linked with the liquid breakup length, this study focuses on the primary breakup phenomena and the breakup length of the liquid jet emanating from the twin-fluid co-axial flow atomizer. Numerical simulations were performed for a wide range of initial conditions and the breakup length of the spray was validated against the experimental observed by Sivadas et al., [26]. These simulations were carried out using a Eulerian based VOF solver that models the fluid as a continuum. K-Epsilon model was used to predict the turbulent nature of the spray. The air and water velocities were varied between 19.0 to 31.3 m/s and 0.7 to 1.8 m/s respectively. The proposed model was able to predict the computed breakup length within 20% of the experimental values. The present model can be further extended to test for a co-axial swirl injector to predict finer spray formation.

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Journal articles on the topic 'Atomization and Sprays'

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