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1
Panão, Miguel. "Ultrasonic Atomization: New Spray Characterization Approaches". Fluids 7, nr 1 (7.01.2022): 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.
2
Sapit, Azwan, Takashi Yano, Yoshiyuki Kidoguchi i Yuzuru Nada. "Effect of Wall Configuration on Atomization of Rapeseed Oil Diesel Spray Impinging on the Wall". Applied Mechanics and Materials 315 (kwiecień 2013): 320–24. http://dx.doi.org/10.4028/www.scientific.net/amm.315.320.
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Fuel-air mixing is important process in diesel combustion. It has been well known that wall configuration of the piston affects spray atomization. Biomass fuel, that is viable alternative fuel for fossil one, needs great help of mixing to atomization because the fuel has high viscosity and high distillation temperature. This study investigates spray atomization characteristics of rapeseed oil (RO) when it impinges on the piston wall. Optical observation of RO spray was carried out using shadowgraph photography technique. The optical images and image analysis show that wall impingement effectively promotes RO spray atomization. Spray atomization is more sensitive to wall configuration for RO than diesel fuel. The wall that has flat floor at the bottom can improve atomization. It is necessary for RO spray to promote spray penetration followed by wall-impingement because long spray path offers wide spray boundary region to form droplets.
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Post, Scott L., i Andrew J. Hewitt. "Flat-Fan Spray Atomization Model". Transactions of the ASABE 61, nr 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.
4
Ghahremani, Amirreza, Mohammad Ahari, Mojtaba Jafari, Mohammad Saidi, Ahmad Hajinezhad i Ali Mozaffari. "Experimental and theoretical study on spray behaviors of modified bio-ethanol fuel employing direct injection system". Thermal Science 21, nr 1 Part B (2017): 475–88. http://dx.doi.org/10.2298/tsci160108253g.
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One of the key solutions to improve engine performance and reduce exhaust emissions of internal combustion engines is direct injection of bio-fuels. A new modified bio-ethanol is produced to be substituted by fossil fuels in gasoline direct injection engines. The key advantages of modified bio-ethanol fuel as an alternative fuel are higher octane number and oxygen content, a long-chain hydro-carbon fuel, and lower emissions compared to fossil fuels. In the present study spray properties of a modified bio-ethanol and its atomization behaviors have been studied experimentally and theoretically. Based on atomization physics of droplets dimensional analysis has been performed to develop a new non-dimensional number namely atomization index. This number determines the atomization level of the spray. Applying quasi-steady jet theory, air entrainment and fuel-air mixing studies have been performed. The spray atomization behaviors such as atomization index number, Ohnesorge number, and Sauter mean diameter have been investigated employing atomization model. The influences of injection and ambient conditions on spray properties of different blends of modified bio-ethanol and gasoline fuels have been investigated performing high-speed visualization technique. Results indicate that decreasing the difference of injection and ambient pressures increases spray cone angle and projected area, and decreases spray tip penetration length. As expected, increasing injection pressure improves atomization behaviors of the spray. Increasing percentage of modified bio-ethanol in the blend, increases spray tip penetration and decreases the projected area as well.
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Mohandas, Anu, Hongrong Luo i Seeram Ramakrishna. "An Overview on Atomization and Its Drug Delivery and Biomedical Applications". Applied Sciences 11, nr 11 (2.06.2021): 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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Chen, J. L., M. Wells i J. Creehan. "Primary Atomization and Spray Analysis of Compound Nozzle Gasoline Injectors". Journal of Engineering for Gas Turbines and Power 120, nr 1 (1.01.1998): 237–43. http://dx.doi.org/10.1115/1.2818082.
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This work addresses primary atomization modeling, multidimensional spray prediction, and flow characteristics of compound nozzle gasoline injectors. Compound nozzles are designed to improve the gasoline spray quality by increasing turbulence at the injector exit. Under the typical operating conditions of 270-1015 kPa, spray atomization in the compound nozzle gasoline injectors is mainly due to primary atomization where the flow turbulence and the surface tension are the dominant factors. A primary atomization model has been developed to predict the mean droplet size far downstream by taking into account the effect of turbulent intensity at the injector exit. Two multidimensional spray codes, KIVA-2 and STAR-CD, originally developed for high-pressure diesel injection, are employed for the lower-pressure gasoline injection. A separate CFD analysis was performed on the complex internal flows of the compound nozzles to obtain the initial and boundary conditions for the spray codes. The TAB breakup model used in KIVA-2 adequately facilitates the atomization process in the gasoline injection.
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Ghaffar, Zulkifli Abdul, Ahmad Hussein Abdul Hamid i Mohd Syazwan Firdaus Mat Rashid. "Spray Characteristics of Swirl Effervescent Injector in Rocket Application: A Review". Applied Mechanics and Materials 225 (listopad 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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Zhang, Zhen, Yusong Yu i Jie Cao. "Effect of Upstream Valve Opening Process on Dynamic Spray Atomization of Bipropellant Thruster Injector". Micromachines 13, nr 4 (27.03.2022): 527. http://dx.doi.org/10.3390/mi13040527.
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In order to develop a new generation of intelligent satellites, fast-response bipropellant thrusters are required to work in minimum impulse mode without limitation. When a valve is opening, the fluctuation affects downstream spray atomization at the injector, which determines the thruster’s impulse performance, involving combustion efficiency and impulse repeatability. Accordingly, the spray atomization under impulse working condition was investigated to optimize the thruster’s dynamic response. The effects of propellant property, switch speed, valve stroke, and throttle orifice layout are respectively compared in simulation cases using OpenFOAM. The fluctuating flowrate caused by valve opening was simulated and then used as boundary conditions for downstream spray. Among these factors, orifice layout plays the most significant roles in transient spray development. Compared with MMH spray, NTO spray from outer swirl injector is more sensitive to upstream fluctuation. When the upstream flowrate stabilizes faster, the atomization stability can also be enhanced, thereby improving the impulse repeatability of thrusters in combustion. This experimental result was in good agreement with the simulation, thereby showing that only when atomization of MMH spray and NTO spray both develop into a steady state within 5 ms after valve opening can the impulse performance be reliably achieved.
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Sphicas, Panos, i Apostolos Pesyridis. "Diesel Spray Liquid Length Imaging at High Pressure". Energies 16, nr 6 (20.03.2023): 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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Li, Shougen, Chongchong Chen, Yaxiong Wang, Feng Kang i Wenbin Li. "Study on the Atomization Characteristics of Flat Fan Nozzles for Pesticide Application at Low Pressures". Agriculture 11, nr 4 (2.04.2021): 309. http://dx.doi.org/10.3390/agriculture11040309.
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Spraying is the most widely used means of pesticide application for pest control in agriculture and forestry. The atomization characteristics of the nozzles are directly related to the spray drift, rebound, and deposition. Previous research studies have mainly focused on the change pattern of atomization characteristics. Mathematical descriptions of the atomization characteristics of flat fan nozzles are rare, and pesticide application theories are also insufficient. Atomization characteristics mainly include droplet size and velocity. This study analyzes the influence of the spray parameters (spray angle, pressure, and equivalent orifice diameter of nozzles) and the spatial position in the flow field. To obtain the atomization characteristics of flat fan nozzles, the phase Doppler particle analyzer (PDPA) was selected for the accurate measurement of the droplet sizes and velocities at distances 0.30–0.60 m, using low spray pressures (0.15–0.35 MPa). The droplet size and velocity models were then established and validated. The results revealed that the average absolute error of the droplet size model was 23.74 µm and the average relative error was 8.23%. The average absolute and relative errors of the droplet velocity model were 0.37 m/s and 7.86%, respectively. At a constant spray pressure and angle, there was a positive correlation between the droplet size and the equivalent orifice diameter of the nozzles. The test also verified that the spray angle and distance had a negative correlation with the droplet velocity at a given pressure. The spray distance had no effect on the spray axial droplet size at constant spray pressure. In addition, the spray angle greatly affected the droplet velocity along the X-axis; similarly, the spray parameters, especially spray angle, greatly affected the droplet size.
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Balasubramanyam, M. S., C. P. Chen i H. P. Trinh. "A New Finite-Conductivity Droplet Evaporation Model Including Liquid Turbulence Effect". Journal of Heat Transfer 129, nr 8 (7.12.2006): 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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Ding, Hong Yuan, Peng Deng, Xu Yao Mao i Chao Wu. "Flash Boiling Spray Simulation Based on Void Fraction and Superheat Controlling". Applied Mechanics and Materials 737 (marzec 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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Si, Chao Run, Xian Jie Zhang i Jun Biao Wang. "Processing and Microstructure Properties of 7055-Al Alloy Prepared by Low-Pressure Spray Forming". Applied Mechanics and Materials 574 (lipiec 2014): 373–79. http://dx.doi.org/10.4028/www.scientific.net/amm.574.373.
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Spray forming is a new developed advanced metal-forming process, of which the property benefits from rapid solidification. The porosity produced during the atomization progress can obviously decrease the material performance. In this paper, a self-designed Laval-type atomizer is used to improve atomization efficiency. The atomization results show that the atomizer can obtain well atomization effect at a relative lower atomization pressure, and the mass median diameter d50 is 63.5μm and 43.4μm when the atomization gas pressure P0=0.4 and 0.8MPa separately. The technological parameters are optimized by overall considering the atomized droplet size, gas consumption, deposition property, and the metal yield. By the designed atomizer, the as-deposited billet with lower porosity content can be obtained with the technological parameters of the melting temperature T=800°C, atomization pressure P0=0.6MPa, and spray distance h=500mm. Further test with the deposited billet show that the grain size of the spray formed 7055-Al alloy is mainly ranging 10~30μm, which is about one third of that of as-cast billet.
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Djamari, Djati Wibowo, Muhammad Idris, Permana Andi Paristiawan, Muhammad Mujtaba Abbas, Olusegun David Samuel, Manzoore Elahi M. Soudagar, Safarudin Gazali Herawan i in. "Diesel Spray: Development of Spray in Diesel Engine". Sustainability 14, nr 23 (29.11.2022): 15902. http://dx.doi.org/10.3390/su142315902.
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Research and development in the internal combustion engine (ICE) has been growing progressively. Issues such as air pollution, fuel cost, and market competitiveness have driven the automotive industry to develop and manufacture automobiles that meet new regulation and customers’ needs. The diesel engine has some advantages over the gasoline or spark ignition engine, including higher engine efficiency, greater power output, as well as reliability. Since the early stage of the diesel engine’s development phase, the quest to obtain better atomization, proper fuel supply, and accurate timing control, have triggered numerous innovations. In the last two decades, owing to the development of optical technology, the visualization of spray atomization has been made possible using visual diagnostics techniques. This advancement has greatly improved research in spray evolution. Yet, a more comprehensive understanding related to these aspects has not yet been agreed upon. Diesel spray, in particular, is considered a complicated phenomenon to observe because of its high-speed, high pressure, as well as its high temperature working condition. Nevertheless, several mechanisms have been successfully explained using fundamental studies, providing several suggestions in the area, such as liquid atomization and two-phase spray flow. There are still many aspects that have not yet been agreed upon. This paper comprehensively reviews the current status of theoretical diesel spray and modelling, including some important numerical and experimental aspects.
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Hu, Zuxiang, Benyi Zhang i 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, nr 4 (26.03.2023): 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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Yu, Dongling, Zuoxiang Zhu, Jiangen Zhou, Dahai Liao i Nanxing Wu. "Influence of nozzle outlet diameter on the atomization process of zirconia dry granulation". Advances in Mechanical Engineering 13, nr 6 (czerwiec 2021): 168781402110248. http://dx.doi.org/10.1177/16878140211024885.
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In order to predict the atomization characteristics of the atomization process of zirconia dry granulation accurately, the influence of nozzle outlet diameter on the atomization characteristics of the atomization process of zirconia dry granulation is analyzed. The VOF method and RNG k-ε turbulence model are applied to numerically analyze the flow field of pressure-swirl nozzles with different outlet diameters of the atomization process of zirconia dry granulation, and the effects of outlet diameters on the spray cone angle, liquid film thickness, pressure distribution and velocity distribution are analyzed. The result shows that when the outlet diameter is increased from 3 to 4 mm, the diameter of air core and the outlet velocity of atomized liquid are increased, the spray cone angle is increased from 30.5° to 59.7° while the liquid film thickness is decreased, but when the outlet diameter is increased to 5 mm, the diameter of air core and the outlet velocity of atomized liquid are decreased, the spray cone angle is decreased to 27.6°, while the thickness of liquid film is decreased. The spray cone angle, moisture content of zirconia particles corresponding to nozzles with different outlet diameters are measured by the design of atomization experiment platform and the microstructure of zirconia particles are observed, which verifies the correctness of numerical analysis. Taking the atomization performance of nozzle into consideration, the pressure-swirl nozzle with the outlet diameter of 4 mm is better suitable for the atomization process of zirconia dry granulation.
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HAYASHI, Keiichi, i Kiyoshi OHARA. "Atomization Characteristics of Spray-to-Spray Impinging Atomizer." Journal of the Japan Institute of Energy 78, nr 4 (1999): 275–79. http://dx.doi.org/10.3775/jie.78.275.
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Imai, Kenta, Toshiyuki Koganei, Gentaro Nemoto i Tomonao Ohkawara. "Atomization Technology in Spray Drying". Journal of the Society of Powder Technology, Japan 50, nr 7 (2013): 519–22. http://dx.doi.org/10.4164/sptj.50.519.
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Zhou, Yizhang, Steven Lee, Vincent G. McDonell, Scott Samuelson, Enrique J. Lavernia i Robert L. Kozarek. "Characterization of spray atomization of 3003 aluminum alloy during linear spray atomization and deposition". Metallurgical and Materials Transactions B 29, nr 4 (sierpień 1998): 793–806. http://dx.doi.org/10.1007/s11663-998-0138-3.
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Janna, William S. "Research Needs: Industrial Spray Processes, Spray Drying, and Heat Transfer". Applied Mechanics Reviews 41, nr 10 (1.10.1988): 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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Taboada, Martha L., Doll Chutani, Heike P. Karbstein i Volker Gaukel. "Breakup and Coalescence of Oil Droplets in Protein-Stabilized Emulsions During the Atomization and the Drying Step of a Spray Drying Process". Food and Bioprocess Technology 14, nr 5 (19.02.2021): 854–65. http://dx.doi.org/10.1007/s11947-021-02606-1.
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AbstractThe goal of this study was to investigate the changes in oil droplet size in whey protein–stabilized emulsions during the atomization and the subsequent drying step of a spray drying process. For this purpose, experiments were performed in an atomization rig and a pilot spray dryer with two commercial pressure swirl atomizers. By comparing the oil droplet size before atomization, after atomization, and after spray drying, the changes in oil droplet size during each process step were quantified. The effect of oil droplet breakup during atomization was isolated by atomizing emulsions with 1 wt.% oil content and a protein to oil concentration ratio of 0.1. At 100 bar, the Sauter mean diameter of oil droplet size was reduced from 3.13 to 0.61 μm. Directly after breakup, coalescence of the oil droplets was observed for emulsions with a high oil content of 30 wt.%, leading to a droplet size after atomization of 1.15 μm. Increasing the protein to oil concentration ratio to 0.2 reduced coalescence during atomization and oil droplets with a mean diameter of 0.92 μm were obtained. Further coalescence was observed during the drying step: for an oil content of 30 wt.% and a protein to oil concentration ratio of 0.1 the mean droplet size increased to 1.77 μm. Powders produced at high oil contents showed a strong tendency to clump. Comparable effects were observed for a spray drying process with a different nozzle at 250 bar. The results confirm that droplet breakup and coalescence during atomization and coalescence during drying have to be taken into consideration when targeting specific oil droplet sizes in the product. This is relevant for product design in spray drying applications, in which the oil droplet size in the powder or after its redispersion determines product quality and stability.
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Shen, Yi Jun, Tien Chu Lin i Muh Ron Wang. "Production of Carbon Dioxide Snow by Flash-Atomization for Material Cleaning Process". Advanced Materials Research 569 (wrzesień 2012): 282–85. http://dx.doi.org/10.4028/www.scientific.net/amr.569.282.
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This paper investigates the production of CO2 snow by flash-atomization of liquid carbon dioxide for material cleaning process. The evolution of flash-atomization processes was recorded by means of high-speed shadowgraph. Results shows that the degree of superheat condition of liquid CO2 greatly influence the atomization modes, bobbles growth rate and concentration, and thus result in difference spray angle, spray pattern, and the structure of liquid jet which is suitable for different material cleaning applications. It is found that the spray angle first slowly increases with increase in the degree of superheat (ΔT) under external flash atomization processes. It is increased drastically as the spray transform from external-flashing to internal-flashing mode. Finally the spray angle is decreased again because of the decrease of mass flowrate due to the internal flashing processes . Moreover, the spray angle is increased as the length-to-diameter ratio (L/D) is increased. This is due to the higher bobble growth rate in terms of different pressure distribution and bobble growth time. It is also found that the external-flashing disappears at higher L/D because of the heat transfer to the liquid carbon dioxide. It is concluded that the superheated condition is useful in the control of the spray angle for material cleaning processes.
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Li, Haifu, Jihong Feng, Xinyue Cao, Zhen Zhang, Hongbo Liang i Yusong Yu. "Simulation Study of the Swirl Spray Atomization of a Bipropellant Thruster under Low Temperature Conditions". Energies 15, nr 23 (23.11.2022): 8852. http://dx.doi.org/10.3390/en15238852.
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The spray atomization of an injector significantly influences the performance and working life span of a bipropellant thruster of a spacecraft. Deep space exploration requires the thruster to be able to operate reliably at a low temperature range from −40 °C to 0 °C, so the effect of low temperature conditions on the atomization characteristics of injector spray is motivated to be comprehensively investigated. To study the swirl atomization characteristics of MMH (methylhydrazine), which is more difficult to atomize than NTO (nitrogen tetroxide), numerical simulations were conducted, employing the methods of VOF (volume of fluid) and LES (large eddy simulation) under low temperature conditions. The physical model with a nozzle size of 0.5 mm and boundary conditions with a velocity inlet of 3.89 m/s both follow the actual operation of thrusters. The development of spray atomization at low temperatures was observed through parametric comparisons, such as spray velocity, liquid total surface area, droplet particle size distribution, spray cone angle and breakup distance. When the temperature decreased from 20 °C to −40 °C at the same condition of flowrate inlet, those atomization characteristics of MMH propellant vary following these rules: the spray ejection velocity of MMH is significantly reduced by 7.7%, and gas-liquid disturbance sequentially decreases; the liquid film development is more stable, with a negative influence on atomization quality, causing difficulties for primary and secondary breakup, so the total surface area of droplets also decreases by 6.4%; the spatial distribution characteristics, spray cone angle and breakup distance vary less than 5%. Therefore, the low temperature condition can directly lower the combustion efficiency of thrusters with obvious performance degradation, but there are no significant changes in the propellant mixing and liquid film cooling. It is concluded that the bipropellant thruster can reliably work at low temperatures around −40 °C for deep space probe operation.
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Villiers, Eugene de, David Gosman i Henry Weller. "DETAILED INVESTIGATION OF DIESEL SPRAY ATOMISATION USING QUASI-DIRECT CFD SIMULATION(Spray Technologies, Atomization)". Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines 2004.6 (2004): 295–302. http://dx.doi.org/10.1299/jmsesdm.2004.6.295.
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Sapit, Azwan, Mohd Azahari, Mas Fawzi, Amir Khalid i Bukhari Manshoor. "Effect of Air Movement to Spray Development of Rapeseed Oil in Diesel Engine". Applied Mechanics and Materials 554 (czerwiec 2014): 479–83. http://dx.doi.org/10.4028/www.scientific.net/amm.554.479.
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Fuel-air mixing is important process in diesel combustion. Generally there a two air mixing strategy, which is slow fuel – fast air mixing and fast fuel – slow air mixing. Air movement inside the combustion chamber greatly affect the mixing process and made effective fuel air mixing possible. Biomass fuel needs great help of mixing to atomization because the fuel has high viscosity and high distillation temperature. This study investigates the effect of air movement to spray development and atomization characteristics of rapeseed oil (RO). Optical observation of RO spray was carried out using shadowgraph photography technique and also using high speed camera. The results show that fast air movement effectively promotes RO spray atomization, with the RO spray expand outward from the main body through the whole spray length, which suggests fuel dispersion due to fast air movement.
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Liu, Meng, i Yufeng Duan. "Predicting the Liquid Film Thickness and Droplet–Gas Flow in Effervescent Atomization: Influence of Operating Conditions and Fluid Viscosity". International Journal of Chemical Reactor Engineering 11, nr 1 (10.09.2013): 393–405. http://dx.doi.org/10.1515/ijcre-2013-0073.
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Abstract The droplet–gas flow in effervescent atomization was simulated using a comprehensive numerical model. Liquid film thicknesses in the nozzle exit orifice and droplet size distribution at the downstream of spray were calculated. The thickness of liquid film in the nozzle exit orifice increased and approached the droplet size in the primary atomization, as the air–liquid ratio increased. The primary breakup model can accurately predict the Sauter mean diameter in the primary atomization when gas–liquid two-phase flow belongs to the annular flow in the nozzle exit orifice. The viscosity of fluid had minimal influence on the liquid film thickness for spray with fluids, the viscosity of which is significantly greater than that of water. Droplet size initially decreased and then increased along the axial distance because of the secondary atomization and droplet coalescence at the downstream of spray.
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Qu, De Gang, Dong Xiang, Lei Ming He, Guang Hong Duan i Peng Mou. "An Experimental Study of Atomization Characteristics of the Ultrasonic Spray Nozzle". Advanced Materials Research 230-232 (maj 2011): 958–63. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.958.
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The recent development in advanced packaging and MEMS applications has created a need for high aspect ratio lithography processes, ultrasonic spray coating is a very appropriate method to meet this requirement, the parameters of atomization are greatly affected the spray quality. By using a laser-phase Doppler analyzer (PDA), an experimental study was conducted of the atomization characteristics of the ultrasonic spray nozzle, water was used as the liquid to be atomized instead of photoresist and air was used as the auxiliary gas instead of nitrogen, the parameters of atomization characteristics under different operating conditions were measured, such as mean diameter D10 and diameter distribution of atomized droplet particles etc. The experimental measurement results indicate that the flow rate of atomized liquid and auxiliary gas have a significant impact on the spray characteristics, the nozzle can achieve a comparatively good atomization state under the condition of a relatively small flow rate of atomized liquid or a relatively high flow rate of auxiliary gas, the mean diameter D10 of droplets can be 18.39μm. The research findings can provide an underlying basis for the application of the ultrasonic spray nozzle.
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Sparacino, Berni, d’Adamo, Krastev, Cavicchi i Postrioti. "Impact of the Primary Break-Up Strategy on the Morphology of GDI Sprays in 3D-CFD Simulations of Multi-Hole Injectors". Energies 12, nr 15 (26.07.2019): 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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Taboada, Martha L., Esteban Zapata, Heike P. Karbstein i Volker Gaukel. "Investigation of Oil Droplet Breakup during Atomization of Emulsions: Comparison of Pressure Swirl and Twin-Fluid Atomizers". Fluids 6, nr 6 (11.06.2021): 219. http://dx.doi.org/10.3390/fluids6060219.
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The goal of this study was to investigate oil droplet breakup in food emulsions during atomization with pressure swirl (PS), internal mixing (IM), and external mixing (EM) twin-fluid atomizers. By this, new knowledge is provided that facilitates the design of atomization processes, taking into account atomization performance as well as product characteristics (oil droplet size). Atomization experiments were performed in pilot plant scale at liquid volume flow rates of 21.8, 28.0, and 33.3 L/h. Corresponding liquid pressures in the range of 50–200 bar and air-to-liquid ratios in the range of 0.03–0.5 were applied. Two approaches were followed: oil droplet breakup was initially compared for conditions by which the same spray droplet sizes were achieved at constant liquid throughput. For all volume flow rates, the strongest oil droplet breakup was obtained with the PS nozzle, followed by the IM and the EM twin-fluid atomizer. In a second approach, the concept of energy density EV was used to characterize the sizes of resulting spray droplets and of the dispersed oil droplets in the spray. For all nozzles, Sauter mean diameters of spray and oil droplets showed a power-law dependency on EV. PS nozzles achieved the smallest spray droplet sizes and the strongest oil droplet breakup for a constant EV. In twin-fluid atomizers, the nozzle type (IM or EM) has a significant influence on the resulting oil droplet size, even when the resulting spray droplet size is independent of this nozzle type. Overall, it was shown that the proposed concept of EV allows formulating process functions that simplify the design of atomization processes regarding both spray and oil droplet sizes.
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Liu, Kai. "Research of the Atomization Characteristics of Low Pollution Air Blast Nozzle". Advanced Materials Research 655-657 (styczeń 2013): 133–36. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.133.
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Atomization characteristic has great impact about combustion efficiency, ignition performance, and outlet temperature field of combustor. Obtained atomization characteristic about spray particle size and spray cone angle using LDV/PDPA system and the relevant software. The results indicated: particle size decrease rapidly with increasing air and tends to stabilize, Spray cone angle does not change with the air pressure. These experimental data have provided reliable basis for the nozzle group design, development and operation.
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Jassim, Ahmad K., Basim A. Abd Alhay, Rakad K. Abd Al Kadhim, Fatima Kh Hato i Dhaa A. Hashim. "A Comparison of Soybean Oil Methyl Ester and Diesel Sprays behavior and atomization characteristics". Journal of Petroleum Research and Studies 7, nr 1 (6.05.2021): 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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Jasim, Noor Mohsin. "A Comparison of Soybean Oil Methyl Ester and Diesel Sprays Behavior and Atomization Characteristics". Journal of Petroleum Research and Studies 7, nr 4 (7.05.2021): 65–79. http://dx.doi.org/10.52716/jprs.v7i4.206.
Pełny tekst źródłaStreszczenie:
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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Han, Han, Pengfei Wang, Ronghua Liu, Yongjun Li, Jan Wang i Yidan Jiang. "Experimental study on atomization characteristics of two common spiral channel pressure nozzles". E3S Web of Conferences 81 (2019): 01022. http://dx.doi.org/10.1051/e3sconf/20198101022.
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Spiral channel pressure nozzles are commonly used pressure nozzles in practical workplaces. In this paper, two kinds of spiral channel type pressure nozzles, namely, spiral hole type and spiral non-porous type, the atomization characteristics and dust reduction efficiency under different spray pressures are discussed and compared. Based on the experimental method, based on the self-designed spray dust-reducing roadway experimental platform, the macro-atomization characteristics of the two nozzles, namely the flow rate, the atomization angle, the range, and the droplet size, were measured. The following conclusions were drawn: (1) The flow rates of both nozzles increase with increasing spray pressure, and the flow coefficient of the spiral non-porous nozzle is small. (2) The change of the atomization angle of the two nozzles first increases and then decreases with the increase of the spray pressure, and the atomization angle of the spiral non-porous nozzle is larger. At the same time, the range of the two nozzles gradually increases as the spray pressure increases, and the range of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle. (3) When the spray pressure is gradually increased, the droplet size of the two nozzles selected in the experiment is gradually reduced, and the droplet size of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle before 5 MPa, and then gradually Become smaller. The main reason why the droplet size decreases with the increase of the spray pressure is that the increase of the spray pressure leads to an increase in the spray speed of the water droplets, so that the water droplets are completely split when they are ejected from the nozzle, resulting in a smaller droplet size. In summary, when the spray pressure required in the actual working environment is low, the use of a spiral non-porous nozzle is more conducive to dust reduction.
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FAN, XIAOFENG, i JIANGFENG WANG. "A MARKER-BASED EULERIAN-LAGRANGIAN METHOD FOR MULTIPHASE FLOW WITH SUPERSONIC COMBUSTION APPLICATIONS". International Journal of Modern Physics: Conference Series 42 (styczeń 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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Raghu, P., N. Nallusamy i Pitchandi Kasivisvanathan. "Spray Characteristics of Diesel and Biodiesel Fuels for Various Injection Timings under Non Evaporating Conditions". Applied Mechanics and Materials 787 (sierpień 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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Kim, Kihyun, i Ocktaeck Lim. "Investigation of the Spray Development Process of Gasoline-Biodiesel Blended Fuel Sprays in a Constant Volume Chamber". Energies 13, nr 18 (15.09.2020): 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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Seyedin, Seyed Hadi, Majid Ahmadi i Seyed Vahid Seyedin. "Design and construction of the pressure swirl nozzle and experimental investigation of spray characteristics". Tehnički glasnik 13, nr 3 (24.09.2019): 204–12. http://dx.doi.org/10.31803/tg-20180908135420.
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This paper focuses on the structure and performance of the pressure swirl nozzle and the study of liquid atomization. In this study, the atomizer has been designed and some experiments have been performed on it. Since image processing is an efficient method for measuring the size of the droplet and since it considerably reduces the total measuring time and eliminates the subjective observer’s error in sizing and counting spray drops, a digital camera has been used for capturing images and image processing has been done by the MATLAB software. The results show that by increasing the atomization air pressure, the spray angle increases and the droplet’s size decreases. It is concluded that the spray angle is a function of the atomization air pressure and orifice diameter. Moreover, when the distance from the spray centre line increases, the droplet’s average velocity decreases.
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Goodwin, M. S., i 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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CHOI, SEUNG-HUN, i YOUNG-TAIG OH. "SPRAY BEHAVIOR AND ATOMIZATION CHARACTERISTICS OF BIODIESEL". International Journal of Modern Physics: Conference Series 06 (styczeń 2012): 419–24. http://dx.doi.org/10.1142/s2010194512003546.
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Biodiesel has large amount of oxygen in itself, which make it very efficient in reducing exhaust emission by improving combustion inside an engine. But biodiesel has a low temperature flow problem because it has a high viscosity. In this study, the spray behavior and atomization characteristics were investigated to confirm of some effect for the combination of non-esterification biodiesel and fuel additive WDP and IPA. The process of spray was visualized through the visualization system composed of a halogen lamp and high speed camera, and atomization characteristics were investigated through LDPA. When blending WDP and IPA with biodiesel, atomization and spray characteristics were improved. Through this experimental result, SMD of blended fuel, WDP 25% and biodiesel 75%, was 33.9% reduced at distance 6cm from a nozzle tip under injection pressure 30MPa.
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Yan, Qiufeng, Jiahan You, Wanting Sun, Ying Wang, Hongmei Wang i Lei Zhang. "Advances in Piezoelectric Jet and Atomization Devices". Applied Sciences 11, nr 11 (31.05.2021): 5093. http://dx.doi.org/10.3390/app11115093.
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In recent years, the piezoelectric jet and atomization devices have exhibited tremendous advantages including their simple construction, and the fact that they are discreet and portable as well as low cost. They have been widely used in cell printing, spray cooling, drug delivery, and other industry fields. First, in this paper, two different concepts of jet and atomization are defined, respectively. Secondly, based on these two concepts, the piezoelectric jet and atomization devices can be divided into two different categories: piezoelectric micro jet device and piezoelectric atomization device. According to the organizational structure, piezoelectric micro jet devices can be classified into four different models: bend mode, push mode, squeeze mode, and shear mode. In addition, their development history and structural characteristics are summarized, respectively. According to the location of applied energy, there are two kinds of piezoelectric atomization devices, i.e., the static mesh atomization device and the vibration mesh atomization device, and both their advantages and drawbacks are discussed. The research achievements are summarized in three aspects of cell printing, spray cooling, and drug delivery. Finally, the future development trends of piezoelectric jet and atomization devices are prospected and forecasted.
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Xiao, Yinli, Changwu Wang, Zhibo Cao i Wenyan Song. "Laser holography measurement and theoretical analysis of a pressure-swirl nozzle spray". Advances in Mechanical Engineering 10, nr 12 (grudzień 2018): 168781401881325. http://dx.doi.org/10.1177/1687814018813253.
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The characteristic of the spray within combustion chamber is one of the determining factors that affect the performance and exhaust gas emissions of an aero-engine. Recently, the holography technique has been successfully applied to spray atomization measurement due to its significant advances. In this article, an atmospheric test rig of pressure-swirl nozzle is built. The kerosene spray generated at the atmospheric condition and in an aero-engine combustor is measured. The Sauter mean diameter of the spray droplets is obtained. In addition, the theoretical analysis of film formation and sheet breakup processes are conducted. Comparison of theoretical analysis and experimental results on the spray atomization of a pressure-swirl nozzle is presented.
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Bianchi, G. M., P. Pelloni, F. E. Corcione, L. Allocca i F. Luppino. "Modeling Atomization of High-Pressure Diesel Sprays". Journal of Engineering for Gas Turbines and Power 123, nr 2 (7.12.2000): 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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Sapit, Azwan, Mohd Azahari Razali, Mohd Faisal Hushim, M. Jaat, Akmal Nizam Mohammad i Amir Khalid. "Dynamic Behavior of Rapeseed Oil Spray in Diesel Engine". Applied Mechanics and Materials 773-774 (lipiec 2015): 520–24. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.520.
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Fuel-air mixing is important process in diesel combustion which significantly affects the combustion and emission of diesel engine. Due to the nature of biomass fuel that has high viscosity and high distillation temperature, the condition and furthermore the improvement of atomization process is very important. This study investigates the atomization characteristics and droplet dynamic behaviors of diesel engine spray fueled by rapeseed oil (RO). Optical observation of RO spray was carried out using shadowgraph photography technique. Single nanospark photography technique was used to study the characteristics of the rapeseed oil spray while dual nanospark shadowgraph technique was used to study the spray droplet behavior. Using in-house image processing algorithm, the images were processed and the boundary condition of RO spray also was studied. The results show that RO has very poor atomization due to the high viscosity nature of the fuel. This is in agreement with the results from spray droplet dynamic behavior studies that shows due to the high viscosity, the droplets are large in size and travel downward, with very little influence of entrainment effect due to its large kinematic energy.
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Yang, Zhou, Jiaxiang Yu, Jieli Duan, Xing Xu i Guangsheng Huang. "Optimization-Design and Atomization-Performance Study of Aerial Dual-Atomization Centrifugal Atomizer". Agriculture 13, nr 2 (11.02.2023): 430. http://dx.doi.org/10.3390/agriculture13020430.
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The aerial atomizer is the most essential component of the plant protection UAV (unmanned aerial vehicle). However, the structural optimization of existing aerial atomizers lacks comprehensive consideration of spray parameters and structural parameters, and there is a shortage of available atomizer spray models, resulting in the unstable effect of UAV application. In our previous work, an aerial dual-atomization centrifugal atomizer was developed. In order to obtain an aerial atomizer with good atomization effect and its atomization model, structural optimization at different rotation speeds and flow rates of the atomizer, and its atomization performance, are studied in this paper. Firstly, with the droplet volume median diameter (VMD) and spectral width (SRW) as the evaluation index, through the single-factor, Plackett–Burman and Box–Behnken tests, the influence of rotation speed, flow rate, tooth number and tooth shape were studied. The regression models of the droplet VMD and SRW were established using multiple quadratic regression fitting of the test data. Secondly, in order to achieve the lowest droplet VMD and SRW, the response surface method and post-hoc multiple comparison method were used to obtain the optimized structure of the atomizer’s rotation ring at different rotation speeds (600–7000 mL/min) and flow rates (500–1000 mL/min). Lastly, with the effective swath width (ESW) of the optimized atomizer as the evaluation index, through the Box–Behnken test, the influence of rotation speed, flow rate and spray height were studied. The multiple quadratic regression model of ESW was established with the test data. The test results indicated that rotation speed, flow rate and tooth number had a significant effect on droplet VMD and SRW; tooth shape had no significant effect on the droplet VMD and SRW, however, the square tooth shape had the best atomization effect; and rotation speed, flow rate and spray height had a significant effect on ESW. The optimized structural parameters were tooth shape: square, and tooth number: 20. The determination coefficient of the regression model of VMD, SRW and ESW were 0.9976, 0.9770 and 0.9974, respectively, which indicates that the model was accurate, and can evaluate and predict the spray effect. This paper provides an optimized dual-atomization centrifugal atomizer, and its regression models of VMD, SRW and ESW for UAV applications can provide a reference for efficient UAV spraying.
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Lei, Yan, Yue Wu, Dingwu Zhou, Kaixin Wang, Tao Qiu, Yuwan Deng i Dan Zhou. "Investigation on Primary Breakup of High-Pressure Diesel Spray Atomization by Method of Automatic Identifying Droplet Feature Based on Eulerian–Lagrangian Model". Energies 15, nr 3 (25.01.2022): 867. http://dx.doi.org/10.3390/en15030867.
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To investigate primary breakup close to an injector, this paper presents both experimental and numerical research on high-pressure common-rail diesel injection. We propose a new method named SD-ELSA model to realize automatically identifying droplet features for high-pressure diesel spray based on the classic ELSA (Eulerian Lagrangian Spray Atomization) model; this method is suitable for varied injection operation conditions. The SD-ELSA first identifies the liquid bulk due to breakup of the continuous phase in near field, and then converts the Eulerian liquid bulk into Lagrangian particles to complete the calculation of the total spray atomization. The SD-ELSA model adopts two key criteria, i.e., the sphericity (S) and the particle diameter (D); the qualified liquid mass is transformed into Lagrangian particle, realizing the coupling of the Eulerian–Lagrangian model. The SD-ELSA model illustrates the total diesel spray atomization process from the breakup liquid column to the droplets.
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Fan, Minghao. "Spray atomization of high pressure nozzle". Chinese Journal of Mechanical Engineering (English Edition) 17, supp (2004): 253. http://dx.doi.org/10.3901/cjme.2004.supp.253.
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Dan, Tomohisa, Naoki Ohishi, Jiro Senda i Hajime Fujimoto. "Atomization Mechanism in Diesel Fuel Spray." Transactions of the Japan Society of Mechanical Engineers Series B 60, nr 577 (1994): 3192–97. http://dx.doi.org/10.1299/kikaib.60.3192.
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Ellendt, N., R. Schmidt, J. Knabe, H. Henein i V. Uhlenwinkel. "Spray deposition using impulse atomization technique". Materials Science and Engineering: A 383, nr 1 (październik 2004): 107–13. http://dx.doi.org/10.1016/j.msea.2004.02.067.
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Höhne, Patrick, Bjoern Mieller i Torsten Rabe. "Advancing spray granulation by ultrasound atomization". International Journal of Applied Ceramic Technology 17, nr 5 (4.06.2020): 2212–19. http://dx.doi.org/10.1111/ijac.13534.
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van Deventer, Henk, René Houben i Robin Koldeweij. "New Atomization Nozzle for Spray Drying". Drying Technology 31, nr 8 (11.06.2013): 891–97. http://dx.doi.org/10.1080/07373937.2012.735734.
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