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1
Zulkifli Abdul Ghaffar, Salmiah Kasolang, Ahmad Hussein Abdul Hamid, and Zolkapli Eshak. "Experimental Analysis of Tangential-Vane Swirl Atomizer Spray Angle." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 101, no. 2 (2023): 1–7. http://dx.doi.org/10.37934/arfmts.101.2.17.
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A swirl atomizer is a widely applied spray-generating device. The swirling motion of a swirl atomizer is induced either by a tangential inlet or a swirl-generating vane. The swirling effect produces a spray with a wide angle which is important in various applications such as gas cooling, diesel engine combustion, and automatic hand sanitizer. An intense swirling mechanism was reported to significantly affect the spray angle. An attempt was made by combining tangential inlet and swirl-generating vane in a single embodiment to create a more intense swirling effect. The experiment was conducted with pipe flow in transition and turbulence regimes. The shadowgraph technique was applied to acquire the spray images. The images were processed using image processing software. It was found that the combined swirling mechanism produces a wider spray angle compared to the individual tangential inlet swirl atomizer. It was also found that the swirling intensity has a bigger effect on the spray angle than the Reynolds number.
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KANKKUNEN, ARI, SANTERI KOIVISTO, KARI SAARI, MIKA JARVINEN, JAMES BIGGS, and ANDREW JONES. "Experiments and visualization of sprays from beer can and turbo liquor nozzles." February 2022 21, no. 2 (2022): 95–106. http://dx.doi.org/10.32964/tj21.2.95.
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Industrial scale swirl-type black liquor nozzles were studied using water as the test fluid. Simple water spraying experiments were found to be very beneficial for studying and comparing nozzles for black liquor spraying. These kinds of experiments are important for finding better nozzle designs. Three nozzle designs were investigated to understand the functional differences between these nozzles. The pres-sure loss of nozzle 1 (“tangential swirl”) and nozzle 3 (“turbo”) were 97% and 38% higher compared to nozzle 2 (“tan-gential swirl”). Spray opening angles were 75°, 60°, and 35° for nozzles 1, 2, and 3, respectively. Video imaging showed that the nozzles produced sprays that were inclined a few degrees from the nozzle centerline. Spray patter-nation showed all the sprays to be asymmetric, while nozzle 2 was the most symmetric. Laser-Doppler measure-ments showed large differences in spray velocities between nozzles. The spray velocity for nozzle 1 increased from 9 m/s to 15 m/s when the flow rate was increased from 1.5 L/s to 2.5 L/s. The resulting velocity increase for nozzle 2 was from 7 m/s to 11 m/s, and for nozzle 3, it was from 8 m/s to 13 m/s. Tangential flow (swirl) directed the spray 6°–12° away from the vertical plane. Liquid sheet breakup mechanisms and lengths were estimated by analyzing high speed video images. The liquid sheet breakup mechanism for nozzle 1 was estimated to be wave formation, and the sheet length was estimated to be about 10 cm. Sheet breakup mechanisms for nozzle 2 were wave formation and sheet perforation, and the sheet length was about 20 cm. Nozzle 3 was not supposed to form a liquid sheet. Nozzle geometry was found to greatly affect spray characteristics.
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Nasr, G. G., R. A. Sharief, and A. J. Yule. "High Pressure Spray Cooling of a Moving Surface." Journal of Heat Transfer 128, no. 8 (2005): 752–60. http://dx.doi.org/10.1115/1.2217747.
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A novel technique is described for investigating spray cooling of moving hot surfaces. An experimental investigation is described for vertically downwards water sprays impinging on a horizontal steel annulus of 250mm diameter with a surface temperature up to 600°C, and rotating at up to 120rpm, giving a tangential velocity of 1.35ms−1. The central homogeneous zones of sprays from full-cone atomizers are used at pressures up to 2.07MPa and the ranges of impacting spray parameters are 0.98to12.5kgm−2s−1 for mass flux, 49-230μm for volume median drop diameter, and 9.8-32.3ms−1 for impinging velocity (Yule, A. J., Sharief, R. A., and Nasr, G. G., 2000, “The Performance Characteristics of Solid Cone Spray Pressure Swirl Atomizers,” Ann. Tokyo Astron. Obs., 10(6), pp. 627–646). Time histories of the steel temperature, at positions within the annulus, are presented and analyzed to deduce the transient cooling as the instrumented section of the annulus was swept repeatedly under the spray. Discussion is provided on the physical processes occurring on the basis of the observations. Correlation equations derived to find relationships of surface heat flux with the spray and surface parameters provide further insight into these processes. The results confirm results for static surfaces, that droplet size is a relatively weak parameter, while droplet momentum flux and surface velocity are important. As the surface velocity is increased, peak heat transfer rate at the surface reduces, and its position moves downstream with respect to the spray centerline.
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Han, Z., Z. Xu, and N. Trigui. "Spray/wall interaction models for multidimensional engine simulation." International Journal of Engine Research 1, no. 1 (2000): 127–46. http://dx.doi.org/10.1243/1468087001545308.
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Models were developed to describe the spray wall impingement processes that take place in internal combustion engines. In this report focus is placed on the model formulation and experiment assessment of the spray/wall interaction submodels. It is identified that the Leidenfrost phenomenon is very unlikely to occur in a spark ignition (SI) engine including stratified-charge operation in a direct injection spark ignition (DISI) engine. A more comprehensive splashing/deposition threshold function is proposed to include the effects of surface roughness and pre-existing liquid film. Based on the wave phenomena observed on the surface of the liquid crown formed during drop impingement, a new splash breakup model is developed using linear instability analysis. The predicted drop size agrees well with available single-drop impingement experimental data. A new formulation for the post-impingement droplet velocity is also given which uses statistical sampling and jet impingement theory. The proposed models were assessed by comparing computations with two sets of experimental sprays impinging on a flat plate with the use of a pintle nozzle injector for port fuel injection (PFI) engines. The computed spray shape, normal and tangential penetration and droplet size show good agreement with experimental data.
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Ghate, Kushal, and Thirumalachari Sundararajan. "Effects of orifice divergence on hollow cone spray at low injection pressures." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 11 (2018): 4091–105. http://dx.doi.org/10.1177/0954410018813432.
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In this work, the effects of orifice divergence on spray characteristics have been reported. Parameters such as spray cone angle, liquid sheet thickness, coefficient of discharge, break-up length, and Sauter mean diameter are greatly affected by the half divergence angle [Formula: see text] at orifice exit. An experimental investigation is carried out in which water sprays from five atomizers having half divergence angle values of 0°, 5°, 10°, 15°, and 20° are studied at different injection pressures. Image processing techniques are used to measure spray cone angle and break-up length from spray images, whereas the sheet thickness outside the orifice exit is obtained using the scattered light from a thin Nd-YAG Laser beam. Phase Doppler interferometry is also used to obtain the Sauter mean diameter at different axial locations. A few numerical simulations based on the volume of fluid method are included to obtain physical insight of the liquid film development and air core flow inside the atomizer. It is observed that the liquid sheet thickness as well as tangential and radial components of velocity at orifice exit are modified drastically with a change in half divergence angle. As a consequence, the droplet size distribution is also altered by variation in the nozzle divergence angle. The mechanism responsible for such variations in the spray behavior is identified as the formation of an air core or air cone inside the liquid injector as a result of the swirl imparted to the liquid flow.
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Vecchio, C., F. Fabiani, M. E. Sangalli, L. Zema, and A. Gazzaniga. "Rotary Tangential Spray Technique for Aqueous Film Coating of Indobufen Pellets." Drug Development and Industrial Pharmacy 24, no. 3 (1998): 269–74. http://dx.doi.org/10.3109/03639049809085619.
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Zheng, Lei, Rui Zhao, Yong-Le Nian, Jun Liu, and Wen-Long Cheng. "Numerical and experimental study of the effects of tangential to axial velocity ratio and structural parameters inside the nozzle on spray characteristics." Physics of Fluids 35, no. 4 (2023): 043303. http://dx.doi.org/10.1063/5.0140753.
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Pressure swirl nozzles are widely applied in spray cooling, dust removal, and fuel injection. To better connect the nozzle structure with the internal flow to analyze their influence on spray parameters, this paper designs a nozzle structure and uses experimental measurement and computational fluid dynamics simulation methods to investigate the influence of the nozzle's tangential velocity to axial velocity ratio ( vτin/ vzin) and the swirl diversion channel eccentric distance ( dl) on the spray parameters. A phase Doppler particle analyzer was used in the experiment study to determine the spray axial velocity ( vz) and sault mean diameter ( D32). In the simulation investigation, the Eulerian multiphase flow model was used to calculate the multiphase flow field of the spray. The results showed that dl and vτin/ vzin both have an obviously linear relationship to the peak location ( rpeak) of each spray parameter. It means that dl plays similar roles as the vτin/ vzin, which can enhance the swirl strength inside the nozzle and increase the spray cone angle. The rpeak of liquid phase volume fraction ( αw) and D32 of the droplet particle are always greater than the rpeak of vz. The analysis of the flow field inside the spray orifice indicates that as the vτin/ vzin rises, the liquid in the nozzle orifice tends to move farther from the central axis, causing atomization to occur more upstream. This study serves as a reference for the flow analysis and structure design of the pressure swirl nozzle.
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Malkeson, S. P., U. Ahmed, A. L. Pillai, N. Chakraborty, and R. Kurose. "Evolution of Surface Density Function in an Open Turbulent Jet Spray Flame." Flow, Turbulence and Combustion 106, no. 1 (2020): 207–29. http://dx.doi.org/10.1007/s10494-020-00186-2.
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AbstractA three-dimensional Direct Numerical Simulation of an open turbulent jet spray flame representing a laboratory-scale burner configuration has been used to analyse the statistical behaviours of the magnitude of reaction progress variable gradient $$\left| {\nabla c} \right|$$ ∇ c [alternatively known as the Surface Density Function (SDF)] and the strain rates, which affect its evolution. The flame has been found to exhibit fuel-lean combustion close to the jet exit, but fuel-rich conditions have been obtained further downstream due to the evaporation of fuel droplets, which leads to the reduction in the mean value of the SDF in the downstream direction. This change in mixture composition in the axial direction has implications on the statistical behaviours of the SDF and the strain rates affecting its evolution. The mean value of dilatation rate remains positive, whereas the mean normal strain rate assumes positive values where the effects of heat release are strong but becomes negative towards both unburned and burned gas sides. The mean values of dilatation rate, normal strain rate and tangential strain rate decrease downstream of the jet exit. However, the mean behaviours of displacement speed and its components do not change significantly away from the jet exit. The mean values of normal strain rate arising from flame propagation remain positive and thus act to thicken the flame. The mean tangential strain rate due to flame propagation (alternatively the curvature stretch rate) remains negative throughout the flame at all axial locations investigated. The mean effective normal strain rate assumes positive values throughout the flame and it increases in the downstream direction for the present case, which is consistent with the reduction in the peak mean value of the SDF in the axial direction. The mean effective tangential strain rate (alternatively stretch rate) assumes negative values throughout the flame at all axial locations.
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Langner, Marcel, Biwen Zhou, Florian Priese, and Bertram Wolf. "Statistical Investigation of Rotary Fluidized Bed Agglomeration Process with Tangential Spray and In-Line Particle Size Measurement for PAT Process Control." Processes 11, no. 4 (2023): 1066. http://dx.doi.org/10.3390/pr11041066.
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A statistical design of experiments for a rotary fluidized bed agglomeration process is performed to improve both the knowledge of the process and the influence of the process parameters. Agglomerates of a pharmaceutical formulation are manufactured in a laboratory fluidized bed rotor apparatus with a tangential spray nozzle. Particle size is measured in-line over the entire agglomeration process with a spatial filter velocimetry probe installed directly in the process chamber and off-line with dynamic image analysis for comparison. The influence of the process parameters spray rate, spray pressure, rotor speed, and process air temperature on the fluidized bed is investigated using a central composite design. In-line measurement of particle size is possible over the entire rotor process. Spray pressure, spray rate, square of process air temperature, and some interactions proved to be statistically significant. Particle size measured with spatial filter velocimetry and dynamic image analysis indicates good agreement and a similar trend. The successful application of particle size measurement in a fluidized bed rotor agglomeration at a laboratory scale using spatial filter velocimetry to improve process control and reduce the risk of failed batches serves as the basis for transferring to a production scale.
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Chen, Chen, and Zhigong Tang. "Investigation of the spray formation and breakup process in an open-end swirl injector." Science Progress 103, no. 3 (2020): 003685042094616. http://dx.doi.org/10.1177/0036850420946168.
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The spray formation and breakup process in an open-end swirl injector were studied through experiments and numerical simulations. A high-speed shadowgraph system and a high-speed backlight system were adopted to record the spray. Volume of fluid was used as the interface tracking method to capture the evolution process. The filling process of the liquid film inside the injector was captured. The air core formation process as observed in the experiments differed from that depicted by the numerical simulation results. The results revealed that the spray pattern of the cross-section at the tangential inlets also varied during the filling process. The evolution of the holes on the liquid film and ligaments was observed. It was determined that the liquid sheet repeatedly exhibited thinning, instability, shedding, breakup, and coalescence in the spray formation and breakup process. The spray pattern underwent the distorted pencil stage, onion stage, tulip stage, and fully developed stage with the increased injection pressure drop. The formation process of the open-end swirl injector also underwent these four stages under an injection pressure drop of 0.5 MPa.
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Lee, Ingyu, Seokgyu Jeong, Jungsoo Yoon, Gujeong Park, and Youngbin Yoon. "Study on Spray characteristics of Dual-Manifold Injector with Various Tangential Entries." Journal of the Korean Society for Aeronautical & Space Sciences 43, no. 10 (2015): 868–74. http://dx.doi.org/10.5139/jksas.2015.43.10.868.
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Bouffard, J., H. Dumont, F. Bertrand, and R. Legros. "Optimization and scale-up of a fluid bed tangential spray rotogranulation process." International Journal of Pharmaceutics 335, no. 1-2 (2007): 54–62. http://dx.doi.org/10.1016/j.ijpharm.2006.11.022.
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Zhao, Bing Tao, Yi Xin Zhang, and Kai Bin Xiong. "Numerical Simulation of Gas Flow Pattern in Cyclone Spray Scrubber." Advanced Materials Research 233-235 (May 2011): 701–6. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.701.
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The numerical simulation of the fluid flow is presented by CFD technique to characterize the flow pattern of cyclone spray scrubber. In this process, the Reynolds-averaged Navier-Stokes equations with the Reynolds stress turbulence model (RSM) for fluid flow are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the fluid computational domain. According to the computational results, the tangential velocity, axial velocity and turbulence intensity of the gas flow are addressed in the different flowrate. The results indicate that the CFD method can effectively reveal the mechanism of gas flow in the cyclone spray scrubber.
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Chen, Chen, Yang Yang, Xiaorong Wang, and Wenxian Tang. "Effect of geometric and operating parameters on the spray characteristics of an open-end swirl injector." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 12 (2019): 4457–67. http://dx.doi.org/10.1177/0954410018824519.
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To study the influence of geometric and operating parameters on the spray characteristics of an open-end swirl injector, seven injectors with different tangential inlet diameters ( D p) and injector length to injector orifice diameter ( L/D) ratios were tested and simulated. Using high-speed backlight, the evolution laws of liquid film thickness, discharge coefficient, spray cone angle, breakup length, and velocity distribution in the swirl chamber under different geometric and operating parameters were captured after unified image processing. Low-injection pressure drop is directly proportional to the discharge coefficient and the spray cone angle. When the injection pressure drop approaches or reaches a critical value of 0.4 MPa, the discharge coefficient and spray cone angle remain nearly constant with maximum fluctuations of 1% and 5%, respectively. With an increase in the geometric characteristic constant A, the liquid film thickness, discharge coefficient, breakup length, and velocity in the swirl chamber decrease, whereas the spray cone angle increases. As the viscous effect increases for increasing L/D, the discharge coefficient and breakup length increase, whereas the spray cone angle decreases. Based on experiment results, empirical formulas for the discharge coefficient, spray angle, and breakup length were put forward as reference for engineering applications, including the effect of the geometric and operating parameters.
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Vo, Tuyen, and Nam Thanh Nguyen. "RESEARCH ON NUMERICAL SIMULATION FOR VELOCITY DISTRIBUTION OF SWIRLING TURBULENT JETS IN SPRAY IRRIGATION TECHNOLOGY." Science and Technology Development Journal 13, no. 2 (2010): 93–99. http://dx.doi.org/10.32508/stdj.v13i2.2121.
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In spray irrigation technology, the change of the basic parameters of the flowfteld has relationship directly with the coefficient of swirling intensity coefficient s, with each value of swirling coefficient differently then the distribution of parameters in flow field also variedly. Remarkably change when the coefficient of swirl intensity changes through the variables as axial velocity u, tangential velocity w; the change of radial velocity V related to turbulent intensity.
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Yadav, Nagendra P., and Abhijit Kushari. "Spray Formation in a Twin-Fluid Internally Mixed Atomizer with Tangential Air Intake." Particle & Particle Systems Characterization 28, no. 1-2 (2011): 25–32. http://dx.doi.org/10.1002/ppsc.201100042.
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Mehta, P. S., S. K. Singal, and B. P. Pundir. "A Comprehensive Simulation Model for Mixing and Combustion Characteristics of Small Direct Injection Diesel Engines." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 209, no. 2 (1995): 117–26. http://dx.doi.org/10.1243/pime_proc_1995_209_192_02.
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An analytical model has been developed to predict the fuel-air mixing and burning characteristics of small direct injection (DI) diesel engines. Four mass and momentum conservation equations are written along the tangential and normal directions to the spray for both free and wall regions based on the continuum integral approach. The spray structure is multi-zonal and the simulation of atomization, droplet-size distribution, evaporation, turbulent mixing and combustion processes is included. The model predictions show good correlation with the experimental data and respond well to the variations in input parameters. The level of predictions from the model is satisfactory and the model is quite suitable to optimize the injection characteristics bowl geometry and air motion in small DI diesel engines.
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Dash, S. K., M. R. Halder, M. Peric, and S. K. Som. "Formation of Air Core in Nozzles With Tangential Entry." Journal of Fluids Engineering 123, no. 4 (2001): 829–35. http://dx.doi.org/10.1115/1.1412845.
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The process of formation of air core and its development with time, inside one cylindrical and one conical nozzle having two tangential entries, has been analyzed experimentally and numerically. Experiments have been carried out using Plexiglas nozzles and water in ambient air; the air core has then been photographed for different nozzles and flow parameters. Numerical simulations have been performed using a finite volume method that employs unstructured grids with cell-wise local refinement and an interface-capturing scheme to predict the shape of the air core. The shape of the air core inside the cylindrical nozzle is found to be helicoidal at steady state for higher inlet velocity, whereas the shape of the free surface remains nearly cylindrical for low inlet velocity. In the conical nozzle, the air core is nearly axisymmetric in experiments. So only two-dimensional simulations are performed; the air core widens at the end of conical section as it approaches nozzle exit. For both nozzles numerical simulation predicts qualitatively and to a large extent also quantitatively the correct shape of the air core and the angle of the spray at the nozzle exit, as verified by comparisons with experimentally observed shapes.
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Krištof, Ondřej, Pavel Bulejko, and Tomáš Svěrák. "Experimental Study on Spray Breakup in Turbulent Atomization Using a Spiral Nozzle." Processes 7, no. 12 (2019): 911. http://dx.doi.org/10.3390/pr7120911.
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Spiral nozzles are widely used in wet scrubbers to form an appropriate spray pattern to capture the polluting gas/particulate matterwith the highest possible efficiency. Despite this fact, and a fact that it is a nozzle with a very atypical spray pattern (a full cone consisting of three concentric hollow cones), very limited amount of studies have been done so far on characterization of this type of nozzle. This work reports preliminary results on the spray characteristics of a spiral nozzle used for gas absorption processes. First, we experimentally measured the pressure impact footprint of the spray generated. Then effective spray angles were evaluated from the photographs of the spray and using the pressure impact footprint records via Archimedean spiral equation. Using the classical photography, areas of primary and secondary atomization were determined together with the droplet size distribution, which were further approximated using selected distribution functions. Radial and tangential spray velocity of droplets were assessed using the laser Doppler anemometry. The results show atypical behavior compared to different types of nozzles. In the investigated measurement range, the droplet-size distribution showed higher droplet diameters (about 1 mm) compared to, for example, air assisted atomizers. It was similar for the radial velocity, which was conversely lower (max velocity of about 8 m/s) compared to, for example, effervescent atomizers, which can produce droplets with a velocity of tens to hundreds m/s. On the contrary, spray angle ranged from 58° and 111° for the inner small and large cone, respectively, to 152° for the upper cone, and in the measured range was independent of the inlet pressure of liquid at the nozzle orifice.
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Alves, Alexandre, Pedro Teixeira Lacava, and Cristiane Aparecida Martins. "Effects of the number of tangential passages on spray characteristics of a bipropellant atomizer." Journal of the Brazilian Society of Mechanical Sciences and Engineering 36, no. 3 (2013): 583–90. http://dx.doi.org/10.1007/s40430-013-0101-3.
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Cejpek, Ondřej, Milan Malý, Miloslav Bělka, and Jan Jedelský. "Replication of Pressure Swirl Atomizer by 3D Printing and Influence of Surface Roughness on the Atomization Quality." MATEC Web of Conferences 328 (2020): 01007. http://dx.doi.org/10.1051/matecconf/202032801007.
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The replication of atomizers by 3D printing technology is a new approach of producing the pressure swirl atomizers. The surface roughness of 3D printed products and manufacturing accuracy of the 3D printing process influence the atomization of the liquid. The high-speed visualization of a spray, produced by scaled 3D printed atomizer, was performed. The spray stability, cone angle and breakup length were determined. Scaled 3D printed atomizers were tested at equivalent pressures of 0.25, 0.5 and 1 bar. Non-dimensionless parameter, Reynolds number, was preserved for the scaled atomizer. The effect of the surface roughness of the tangential ports, swirl chamber and discharge orifice on atomization was assessed at non-scaled pressure swirl atomizer. The roughness of a swirl chamber was created by corundum and ballotin blasting. The inlet pressures of 2.5, 5 and 10 bar were tested.
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Arnt, A. B. C., Márcio Roberto da Rocha, Elidio Angioletto, and J. Meller. "Evaluation of Changes in Microstructural Coatings Deposited by Thermal Spray." Materials Science Forum 727-728 (August 2012): 476–79. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.476.
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In this work, microstructural changes in coatings deposited by hypersonic thermal spraying technique (HVOF) were subjected to adhesive wear tests. Materials subjected to wear lose efficiency, increase costs and direct or indirect way can stop large production systems. The mechanisms involved in this type of wear can be minimized by the microstructural changes that in many cases reduces or stops the loss of material. To perform this assessment coatings compounds of Cr3C225 (80 Ni-20 Cr) e Al2O3.TiO2 (87-13) investigated had similar hardness values (1000 HV) and chemical characteristics. Were subjected to the ASTM G99 using commercial hard metal pin 2 mm, load 50N force and tangential velocity of 0.5 m/s. Worn surfaces and debris were analyzed by optical microscopy, scanning electron microscope and mass loss. The results show high resistance sprayed coatings worn surfaces and debris were fragile nature with little loss of material during the tests.
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Tushar, Tonge* Shilpa Borkar Jagdish Baheti. "A Review on Multiple Unit Pellet System (MUPS) Delivery Systems." International Journal of Pharmaceutical Sciences 3, no. 5 (2025): 4474–90. https://doi.org/10.5281/zenodo.15533086.
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The pharmaceutical industry is currently concentrating on creating novel drug delivery systems that improve therapeutic efficacy and lessen adverse effects. When a medication product needs to be administered in a modified release pattern to senior patients, the oral drug delivery system becomes problematic, particularly because they have trouble swallowing. The design of solid dosage forms has made extensive use of Multiple Unit Pellet Systems (MUPS) tablets in recent years. One of the more recent and difficult technologies that combines the benefits of tablets with pellet-filled capsules in a single dose form is the compaction of multiarticulate, also known as the Multiple Unit Pellet System (MUPS). The method of palletization was initially developed in the 1950s, when the first product was released into the market. Multi-unit dose forms have received a lot of attention lately since their smaller particle sizes allow them to pass through the GI tract more readily. When compared to monolithic dose forms, MUPS is thought to have pharmacokinetic benefits. MUPS consistently offers numerous opportunities to create oral formulations with controlled release and delayed release, which aids in the creation of new pharmaceuticals.
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Kurniawan, Muhammad Helmi, Khusnul Khotimah Ayuningtiyas, and Ridho Dwi Syahrial. "Experimental study of a breastshot waterwheel with the degree of inclination of the nozzle spray against the tip speed ratio." International Journal of Basic and Applied Science 11, no. 4 (2023): 149–60. http://dx.doi.org/10.35335/ijobas.v11i4.139.
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The energy crisis is a severe problem facing the world, including Indonesia. Along with the times, innovation is needed to implement sustainable energy. Non-fossil energy sources have not been widely used, and efforts are still needed to utilize these energy sources. The waterwheel was the first device used in water production. One of the innovations for the sustainability of non-fossil energy is to make a waterwheel. There are still several waterwheels in Indonesia, but an investigation is needed to determine their condition. So in this study, investigating the breastshot water wheel uses a nozzle-based construction with variations in the degree of inclination of the spray against the TSR value. The results showed that the greater the inclination of the nozzle angle, the higher the velocity of the water flow when it enters the wheel. Adding water speed to this wheel will increase the momentum and tangential force. An increase in the tangential force will increase the wheel's torque so that the wheel strength will increase. This increase in power will, of course, result in greater efficiency, thereby increasing the tip speed ratio (TSR).
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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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Piras, M., L. Marchitto, and C. Tornatore. "Supercritical water injection in a single cylinder research engine: a PIV study." Journal of Physics: Conference Series 2590, no. 1 (2023): 012007. http://dx.doi.org/10.1088/1742-6596/2590/1/012007.
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Abstract This work presents the experimental results of a fluid dynamic investigation to characterize the injection of supercritical water in the combustion chamber of an internal combustion engine. Particle Image Velocimetry (PIV) analysis is carried out in an optically accessible 2-stroke Diesel engine. A prechamber, equipped with two optical accesses is connected to the main cylinder through a tangential duct so that the piston stroke induces a swirled motion field with angular velocities typical of light duty engines for automotive application. The engine is equipped with an injection system for the production and injection of supercritical water, with the possibility to independently regulate the injection pressure, temperature, duration, and timing. Tests have then been carried out under different operating conditions to evaluate the impact of the fluid dynamics in the combustion chamber on the water spray. First, the airflow velocity field has been characterized at different engine crank train angles. The water spray has been macroscopically characterized for an injection temperature of 300°C and pressure of 30Mpa. Then, the supercritical water/air interaction has been explored, at different injection pressure, temperature, and Start of Injection (SOI) to provide global information in terms of spray morphology, tip penetration, and velocity vector distribution of the water droplets within the combustion chamber for different injection strategies.
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Michaud, Louis Marc. "Controlled tornadoes could fix climate and energy problems." Clean Energy Science and Technology 2, no. 4 (2024): 232. https://doi.org/10.18686/cest232.
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Stationary tornadoes will be produced by having warm humid air enter the bottom of a hollow tower tangentially. A large atmospheric vortex engine (AVE) could generate 2 GW of electricity. 2000 AVE’s could provide current world electricity needs. The tower would look like a 200 m high natural draft cooling tower. The vortex is started by heating the air with steam or fuel. Subsequently, the vortex is sustained by warm humid surface air, warm sea water spray, or waste heat. Mechanical energy would be produced by expanding air into the low pressure at the base of the vortex via peripheral turbo-generators located at grade and not by harnessing the kinetic energy of the swirling tornado wind. The intensity and size of the vortex can be controlled because the energy is produced by the expansion of surface air which is in a metastable state. Vortex diameter could be 10 m to 100 m. Vortex height could be up to 15 km. The Singapore Science Center fire whirl producer demonstrates that tangential air entries plus a heat source can produce vortices. The technology needs scaling up. Waterspouts demonstrate that low temperature heat sources can produce stable vortices.
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Li, Xiang, Xuewen Zhang, Tianya Zhang, et al. "Insights into Microscopic Characteristics of Gasoline and Ethanol Spray from a GDI Injector Under Injection Pressure up to 50 MPa." Sustainability 16, no. 21 (2024): 9471. http://dx.doi.org/10.3390/su16219471.
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Nowadays it has become particularly valuable to control the Particulate Matter (PM) emissions from the road transport sector, especially in vehicle powertrains with an Internal Combustion Engine (ICE). However, almost no publication has focused on a comparison of the microscopic characteristics of gasoline and ethanol spray under injection pressure conditions of more than 30 MPa, except in the impingement process. By using a Phase Doppler Particles Analyser (PDPA) system, the microscopic characteristics of gasoline and ethanol spray from a Gasoline Direct Injection (GDI) injector under injection pressure (PI) up to 50 MPa was fully explored in this research. The experimental results demonstrate that under the same PI, the second peak of the probability (pd) curves of droplet normal velocity for gasoline is slightly higher than that of ethanol. Moreover, gasoline spray exceeds ethanol by about 5.4% regarding the average droplet tangential velocity at 50 mm of jet downstream. Compared to ethanol, the pd curve’s peak of droplet diameter at (0, 50) for gasoline is 1.3 percentage points higher on average, and the overall Sauter mean diameter of gasoline spray is slightly smaller. By increasing PI from 10 MPa to 50 MPa, pd of the regions of “100 ≤ Weber number (We) < 1000” and “We ≥ 1000” increases by about 23%, and the pd of large droplets over 20 μm shows a significant reduction. This research would provide novel insights into the deeper understanding of the comparison between gasoline and ethanol spray in microscopic characteristics under ultra-high PI. Additionally, this research would help provide a theoretical framework and practical strategies to reduce PM emissions from passenger vehicles, which would significantly contribute to the protection and sustainability of the environment.
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Wang, Yan Hua, Shi Chun Yang, and Yun Qing Li. "Numerical Simulation of Transient Flow Inside Nozzle on Gasoline Direct Injection Engine." Advanced Materials Research 466-467 (February 2012): 1237–41. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.1237.
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To achieve transient flow characteristics at exit of nozzle orifice on gasoline direct injection engine, two phase Euler-Euler schemes was used to simulate the internal flow of the swirl nozzle. Different flow characteristics were calculated in the simulation. Different kinds of nozzle configuration were studied. Cavitaion and swirl flow occured in the nozzles. Injection hole configuration matters more than area variation of swirl tangential slot to discharge coefficient of the studied nozzle. Discharge coefficient changes a little along the injection hole length. The area of the swirl tangrntial slot plays an important throttling action in nozzle internal flow. Smaller area of swirl tangential slot generates larger degree cavitation but smaller mean injection velocity. Turbulence kinetic energy changes with the time of cavitation and swirl field occurring and the nozzle configuration. Before the appearance of cavitation, smaller inclination angle of orifice can generate more turbulence kinetic energy. After that moment, turbulence kinetic energy varies with different configuration. Along injection hole length, turbulence kinetic energy obviously varies. These flow characteristics affect primary atomization and will be as input for next spray simulation. They are also applied to design reference for injection nozzle.
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Ruhyat, Nanang. "COMPARISON OF THE DRYER AIR INLET POSITION ON THE SPRAY DRYER WITH A DOUBLE CONDENSER TO PRODUCE A ROTATING FLOW THROUGHOUT THE DRYING CHAMBER: CFD ANALYSIS." International Journal of Innovation in Mechanical Engineering and Advanced Materials 5, no. 1 (2023): 16. http://dx.doi.org/10.22441/ijimeam.v5i1.21605.
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Simulation of the drying air and the spray of liquid in the spray dryer chamber with Discrete Phase Material (DPM) and Discrete Random Walk (DRW) was presented in this study using CFD methods to analyze the drying liquid. The main problem in spray drying is the adhesion of the material to the drying chamber walls, which causes uneven drying material. This adhesion can slow down the drying process and reduce productivity. The design of the drying air inlet into the drying chamber becomes essential to research. Variations in the position of the drying air inlet into the drying chamber are carried out in the 3D spray dryer room to see the mechanism of the centrifugal velocity of the drying airflow, which can improve uniform mixing with flow resistance due to friction with small walls and the drying air velocity. This phenomenon is impossible to observe in experiments. A geometric model consisting of 1,054,000 hexa-mesh elements at the area around the nozzle, the top spot of the chamber and the remaining area covered with a tetrahedral mesh, was determined to predict velocity, temperature, and fluid flow behavior. The first position, the dryer air inlet, is at an angle from the diameter of the spray drying chamber. The second position is in the middle of the diameter of the drying chamber. The position of the first inlet produces a more even temperature contour with a more tangential velocity due to the small frictional resistance with the walls. At the same time, the second position is not recommended because the flow leads to one side of the wall and creates sticking and even material buildup. A double-heated condenser can dry air at moderate temperatures, and it is a very effective drying product— positioning the dryer air inlet into the drying chamber, achieving the economical production of high-quality products.
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Shi, Wei, Xia Zhang, and Cong Shen. "The Optimization Calculation Method Study on Longitudinal Lattice Girder of the Spray Anchor Bracing System." Advanced Materials Research 368-373 (October 2011): 1975–80. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.1975.
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As the structure component of the spray anchor bracing system, at present the structure calculation method of the longitudinal lattice girder use more simple beam, continuous beam. In order to further research the calculation theory and applicability of the longitudinal lattice girder structure, making the calculation method reflect the mechanical properties of the longitudinal lattice girder accurately, this paper through the use of ANSYS finite element numerical simulation method[1], and the improved method of Winkler[3], considering the impact of the tangential component of the anchor rod axial force, and considering the impact of excavation conditions of the deep foundation pit actual, compare the calculation results of the internal force of the longitudinal lattice girder, concluded the optimization calculation method of the longitudinal lattice girder and the applicability.
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Zhang, Xiaoyu, Xiaolei Zhang, Runze Duan, and Lujia Liu. "Effect of Hydrophilicity/Hydrophobicity of the Injector Wall on Atomization Performance." International Journal of Aerospace Engineering 2022 (October 4, 2022): 1–8. http://dx.doi.org/10.1155/2022/2152543.
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Hydrophilicity/hydrophobicity is a common physical property of the material. Water droplets roll on lotus leaf, and a lot of dust and dirt on the surface of the lotus leaf will be taken away, playing a certain cleaning role. The hydrophobic surface has drag reduction effect that would produce slip on the hydrophobic wall. There are some studies on hydrophilicity/hydrophobicity in channels, most of which focus on the effect of surface drag reduction and heat transfer on microchannels. However, few people pay attention to the effect of the hydrophilicity/hydrophobicity of the injector inner wall on the atomization performance. In this paper, three groups of the open-end swirl injector with different tangential channels were designed to study the effect of hydrophilicity/hydrophobicity on atomization performance. The hydrophobic coating was prepared and used on the inner wall of the injector, and the atomization experimental system was built. In the experiment, the liquid film thickness was measured using the conductance method. Details of the liquid film breakup and spray development were recorded with a high-speed camera. The average droplet diameter was measured by the Malvern particle size analyzer. The atomization performance of injectors with different tangential channels on the hydrophilicity/hydrophobicity was compared, and the effect of the velocity profile on the jet stability is discussed.
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Zhao, Longzhi, Minghui Mou, Daoyun Chen, and Minshi Zhong. "Research on the Influence of Surface Defects Under the Influence of Rail Corrosion on the Fatigue Damage of Wheel Rolling Contact." Coatings 15, no. 5 (2025): 589. https://doi.org/10.3390/coatings15050589.
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Heavy rolling contact fatigue (RCF) may be caused by wheel surface defects under the influence of rail corrosion, which threatens the operational safety of rail vehicles. To investigate the role of surface defects on wheel RCF damage under the influence of rail corrosion, a salt spray tester was used to corrode the rails, an impact testing machine was employed to create surface defects, and RCF tests were completed. The role of surface defects on wheel RCF damage was studied by monitoring the wheel defect surface and cross-section. The results indicate that the tendencies of the RCF crack extension of surface defects of different sizes are similar, and they all extend in a C-shape along the tangential force direction. However, the larger the defect size, the later the crack is initiated. The leading edge material is continuously squeezed into the defect by the tangential force, and a larger plastic deformation layer is formed, which causes the RCF at the leading edge to crack more severely. Meanwhile, under the effect of combined normal force and shear stress, the leading edge crack intersects with the middle edge crack, and the leading edge material is spalled off first. Wheel RCF damage and wear are aggravated by rail corrosion, the longer the corrosion time, the more serious the RCF damage and wear, and the earlier the material spalling time, the lower the fatigue life.
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Kim Dung, Nguyen Thi. "RECOVERY OF PECTIC OLIGOSACCHARIDE (POS) FROM PECTIN HYDOLYSATE FOR FUNTIONAL FOODS." Vietnam Journal of Science and Technology 54, no. 4A (2018): 81. http://dx.doi.org/10.15625/2525-2518/54/4a/11981.
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Pectic oligosaccharide (POS) obtained bypartial hydrolysis of pectin is proposed as a new class of prebioticwhich has many beneficial propertiesfor the health of humans and animals. Currently only a small number of researcheshave explored the production process of POS products in laboratory-scale and pilot, however the manufacturing process, as well as the product, has not yet been offered for sale on the market. In this study, several parameters of arecovery processofPOS powder from the pectin hydrolysatehave been established: condense(5 times, by tangential filtration with nanofiltration column 0.3 kDa), precipitate (ratio of ethanol / concentrates: 3/1), spray drying (5 % maltodextrin, inlet air temperature 170 oC, liquid flow rate 2.5 L/h). The total yield of the recovery processes is 67.7 %. The POS product is still stable after 12 months of storage in plastic bags and in bags of tin. Food safety analysis indicate that POS products do not contain mycotoxins, heavymetals, pathogenic microorganisms and the lethal dose LD 50 can not be detected.
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Calzada, D., A. Uribe, J. Ronceros, W. Namay, G. Zapata, and C. Raymundo. "Design of a Hydraulic Turbine Based in a Pressure Swirl Chamber using Ansys CFD." Journal of Physics: Conference Series 2947, no. 1 (2025): 012012. https://doi.org/10.1088/1742-6596/2947/1/012012.
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Abstract This study presents the simulation of internal flow of a hydraulic turbine using CFD based on pressure-swirl atomizer technology, typically used in combustion chambers of rocket engines. The proposed model is equipped with a swirl chamber with stabilizer included, dual manifold system and a rotor, each of these elements will be simulated to validate its functionality, prior to implementation and subsequent experimental testing. The results show that it is possible to produce the spray output jet even if there are interferences within the swirl chamber such as the rotor itself and the stabilizer. In addition, due to the tangential speeds produced within the atomizer may be viable to place a rotor to produce mechanical power. This study serves as a starting point to carry out future experimental tests to validate the generated power and efficiency of the proposed system. The results presented in the document were validated using mathematical equations and numerical simulations using the Ansys Fluent software.
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Li, Xiang, Xing Chen, Niancheng Hong, et al. "A CFD-DEM Simulation of Droplets in an Airless Spray Coating Process of a Square Duct." Coatings 14, no. 3 (2024): 282. http://dx.doi.org/10.3390/coatings14030282.
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The purpose of this paper is to provide a numerical simulation, taking into account the collisional interactions of droplets in an airless rotary spray coating process. The hydrodynamics of gas and droplets are simulated using the CFD-discrete element method (DEM) with the JKR contact model in an airless rotary spray coating process of a horizontal square duct. The surface energy parameter used in the JKR model is calibrated using a virtual accumulation angle test in the funnel device. Based on the distribution of accumulation angles, a suitable surface energy for wall droplets is proposed. A rational gas RNG k-ε model is suggested in accordance with the comparisons of velocities, standard deviations, and the skewness of droplet number fractions from three turbulence models. The simulations of droplet film thicknesses agree with measurements from the literature regarding the film thickness along a vertical panel. The correlations of the exit gas and droplet velocities of sprayer holes are proposed with a discharge coefficient of 0.85 for gas and 5.87 for droplets. A number index of droplets is introduced in order to measure the uniformity of droplet distributions. A low droplet number index is found at low rotational speeds, representing a more uniform distribution of droplets as the rotation speeds reduce within the square duct. The normal force between the droplet and the wall is approximately an order of magnitude larger than the droplet–wall tangential force of collisions.
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Biswas, G., and S. K. Som. "Coefficient of discharge and spray cone angle of a pressure nozzle with combined axial and tangential entry of power-law fluids." Applied Scientific Research 43, no. 1 (1986): 3–22. http://dx.doi.org/10.1007/bf00385725.
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Kou, Baofu, Pengliang Huo, and Xiaohua Hou. "Research on the Influence of External Parameters of Fan-Type Nozzle on Water Jet Performance." Shock and Vibration 2020 (September 22, 2020): 1–16. http://dx.doi.org/10.1155/2020/4386259.
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At present, high-pressure water jet technology occupies a very important position in the automobile washing industry. Some automatic washers cannot meet the washing requirements in the washing process due to unreasonable arrangement of nozzles on their spray rods. Based on the theory of computational fluid dynamics (CFD), the internal and external flow field model of the nozzle are established in this paper. Fluent is used to simulate and analyze the flow field, and the external parameters of the nozzle on the side spray bar of the automatic automobile washer are optimized. The simulation results show that after the nozzle and the normal line of the automobile surface are inclined at a certain angle, the target surface is affected not only by normal striking force but also by tangential pushing force, which makes stains easier to remove. The washing effect is the best when the nozzle is inclined 30° to the normal line of the automobile surface. Increasing the nozzle inlet pressure will increase the dynamic pressure on the automobile surface, but the increase of dynamic pressure will decrease after increasing to a certain pressure. The inlet pressure has little effect on the area covered by water jet. The reasonable matching results of jet angle, nozzle spacing, and nozzle distance from the automobile surface (target distance) obtained by numerical simulation can not only make the automobile surface completely covered and cleaned but also ensure less jet interference and no waste of water from adjacent nozzles. The above research conclusions can provide a basic theoretical basis for the optimal design of automatic automobile washing.
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Johnson, B. V., S. J. Markowski, and H. M. Craig. "Cold Flow and Combustion Experiments With a New Burner Air Distribution Concept." Journal of Engineering for Gas Turbines and Power 108, no. 2 (1986): 370–75. http://dx.doi.org/10.1115/1.3239913.
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Experiments were conducted with a JT8D-engine sized can combustor modified such that all the combustion and dilution air entered through the burner front face from a single plenum through counter-rotating annular swirlers. Cold flow experiments were conducted to visualize and to develop a mixing and recirculation flow pattern within the combustor which contained annular and central recirculation cells and featured rapid mixing in the downstream section of the combustor. Laser velocimeter measurements, downstream of the air inlet configuration used in the combustion experiments, showed the largest velocity gradients in the radial direction were in the tangential velocity profile. Low-pressure combustion experiments were conducted with three flat spray fuel nozzle orientations and three air inlet geometries to determine the general air inlet and fuel injection characteristics required to produce acceptable combustion characteristics with the selected swirler configuration. The combustion experiments included emission, total pressure and total temperature measurements at the burner exit plane. Low emission levels and temperature pattern factors with relatively low burner pressure losses were demonstrated.
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Zhang, Jiajun, Dong Liang, and Yuanwen Cao. "Analysis of Dust Reduction Characteristics of Multistage Tandem Dust Removal System." Shock and Vibration 2023 (June 15, 2023): 1–11. http://dx.doi.org/10.1155/2023/5541196.
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Asphalt hot regeneration pavement maintenance vehicle is a type of in situ heating waste asphalt special vehicle equipment for mix and regeneration of aged asphalt. When waste asphalt mixture is heated and melted, a lot of organic fumes are typically produced, along with dust from the mixing process. Because of the complex composition of the exhaust gases produced by asphalt hot regeneration pavement maintenance vehicles, it can be difficult to purify and remove them using a single method. In order to effectively purify exhaust gas with complicated compositions, a multistage combined treatment dust removal system structure is presented that includes cyclone sections, spray sections, and adsorption sections. With an emphasis on the cyclone section structure with the dust-gas separation function, computational fluid dynamics (CFD) is used to analyze the internal flow field characteristics, turbulence intensity, tangential velocity, and velocity field vector characteristics. The results reveal that the more symmetrical the distribution of tangential velocity field and static pressure field is, the greater the cyclone dust collector’s dust removal efficiency is, the more stable the flow field is, and the lower the turbulence intensity is. Furthermore, the center cyclone’s growing speed is adversely connected with dust removal effectiveness. As a result, an antiventuri cyclone dust collector with a scrambling column was designed. When the inlet air speed is 6 m/s, the dust removal efficiency of the improved device is 97.0%, which is 5.1% higher than that of the original device, and when the inlet air speed is 8 m/s, the dust removal efficiency of the improved device is 97.3%, which is 4.16% higher than that of the original device. With the increase of the inlet air speed, the difference between them keeps decreasing.
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Xu, Min, Paul Wan Sia Heng, and Celine Valeria Liew. "Evaluation of coat uniformity and taste-masking efficiency of irregular-shaped drug particles coated in a modified tangential spray fluidized bed processor." Expert Opinion on Drug Delivery 12, no. 10 (2015): 1597–606. http://dx.doi.org/10.1517/17425247.2015.1054278.
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Karimaei, Hadiseh, Seyed Mostafa Hosseinalipour, and Ramin Ghorbani. "A new energy-based model to predict spray droplet diameter in comparison with momentum-based models." Aircraft Engineering and Aerospace Technology 91, no. 1 (2018): 182–89. http://dx.doi.org/10.1108/aeat-06-2017-0155.
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Purpose To estimate mean droplet diameter (MDD) of a spray, three different numerical models were used in this paper. One of them is investigation of the surface instability of the liquid sheet producing from an injector. Design/methodology/approach First, the linear instability (LI) analysis introduced by Ibrahim (2006) is implemented. Second, the improved (ILI) analysis already introduced by the present authors is used. ILI analysis is different from the prior analysis, so that the instability of hollow-cone liquid sheet with different cone angles is investigated rather than a cylindrical liquid sheet. It means that besides the tangential and axial movements, radial movements of the liquid sheet and gas streams have been considered in the governing equations. Beside LI theory as a momentum-based approach, a new model as a theoretical energy-based (TEB) model based on the energy conservation law is proposed in this paper. Findings Based on the energy-based approach, atomization occurs because of kinetic energy loss. The resulting formulation reveals that the MDD is inversely proportional to the atomization efficiency and liquid Weber number. Research limitations/implications The results of these three models are compared with the available experimental data. Prediction obtained by the proposed TEB model is in reasonable agreement with the result of experiment. Practical implications The results of these three models are compared with the available experimental data. Prediction of the proposed energy-based theoretical model is in very good agreement with experimental data. Originality/value Comparison between the results of new model, experimental data, other previous methods show that it can be used as a new simple and fast model to achieve good estimation of spray MDD.
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Qin, Jianxiu, and Huiqiang Zhang. "Numerical Analysis of Self-Excited Combustion Instabilities in a Small MMH/NTO Liquid Rocket Engine." International Journal of Aerospace Engineering 2020 (July 4, 2020): 1–17. http://dx.doi.org/10.1155/2020/3493214.
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Combustion instabilities in a small MMH/NTO liquid rocket engine used for satellite attitude and course control are numerically investigated. A three-dimensional Navier-Stokes code is developed to simulate two-phase spray combustion for cases with five different droplet Sauter Mean Diameters. As the droplet size increases from 30 microns to 80 microns, pressure oscillations are stronger with larger amplitudes. But an increase of the droplet size in the range of 80 microns to 140 microns indicates a reduction in the amplitudes of pressure oscillations. This trend is the same as the Hewitt criterion. The first tangential (1T) mode and the first longitudinal (1L) mode self-excited combustion instabilities are captured in the 60-micron and 80-micron cases. Abrupt spikes occur in the mass fraction of MMH and coincide with abrupt spikes in the mass fraction of NTO at the downstream regions just adjacent to the impinging points. Thus, local combustible high-dense mixtures are formed, which result in quasiconstant volume combustion and abrupt pressure spikes. The propagation and reflection of pressure waves in the chamber stimulate the combustion instability. When the droplet size is too small or too large, it is difficult to form local high-dense premixtures and combustion is stable in the chamber.
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Gvozdyakov, D. V., and A. V. Zenkov. "Evaluation of the efficiency of air swirl during atomization of coal-water slurries with a pneumatic atomizer." Vestnik IGEU, no. 4 (August 31, 2024): 30–40. http://dx.doi.org/10.17588/2072-2672.2024.4.030-040.
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Due to modern requirements for environmental protection, introduction of environmentally friendly power engineering technologies involves search and development of new energy sources. One of the ways to meet these requirements and maintain the same level of energy production by thermal power plants is to use multicomponent fuels. The most promising and affordable heavy fuel oil from the point of view of energy, ecology and economy are coal-water slurries (CWS). In this regard, the study of the properties and characteristics of such fuels is relevant. The coal-water slurries have been prepared in a rotary hydrodynamic cavitation generator. A pneumatic atomizer with external mixing is used to spray the coal-water slurries. Interferometric Particle Imaging method is used to determine the average size of fuel droplets after atomization. The authors have conducted experimental studies of the characteristics of atomization of coal-water slurries based on lignite and pyrogenetic liquid with a pneumatic atomizer with a tangential supply of a spraying agent. A three-stage method to prepare lignite-based slurries with pyrogenetic liquid has been tested. It has been established that when using this technique, the fluidity of coal-water fuel is maintained even with the introduction of 20 % by weight of pyrogenetic liquid into the composition of coal-water slurries when replacing both water and coal in equal proportions. The kinematic viscosity of coal-water suspensions increases when pyrogenetic liquid is added, despite a decrease in the concentration of the solid component. The change of suspension density is insignificant. The results of the study of atomization process have shown that the tangential air supply to the atomizer leads to an increase of the jet spraying angle by 6° compared with direct supply. At the same time, the average droplet size in the jet of a two-component CWS with direct air supply is 8 % smaller. The results of the study have made it possible to obtain completely new knowledge that can significantly advance domestic and world science and technology in the field of power engineering, namely the technology of coal-water fuels atomization. Experimental studies have determined the main patterns of influence of the CWS properties and the method of spraying agent supply on the formation of a gas-drop jet. Such patterns will provide conditions for the effective atomization of quite viscous CWS in the combustion chambers of energy boilers. The results obtained will enable designers and constructors to develop highly efficient designs of steam and hot water boilers and gasifiers fueled by CWS.
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Fedotov, F. S., and A. M. Telegin. "Simulation of a Magnetic Trap for a Magnetron Sputtering System (MPS) Using the Finite Element Method Using the PYTHON Language Module." LETI Transactions on Electrical Engineering & Computer Science 16, no. 2 (2023): 85–95. http://dx.doi.org/10.32603/2071-8985-2023-16-2-85-95.
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The modeling of a magnetic trap using pyFEMMis considered in order to select it for the design of a laboratory stand with magnetron sputtering in the form of a magnetron sputtering system with a flat cathode. This method of application was not chosen by chance, because it is more practical due to its speed of spraying thin metal films onto the substrate than a diode spray system. A magnetic trap for MSS is a subsystem whose magnetic fields are capable of holding plasma near the target. Using the developed program allows you to select the necessary trap from the proposed magnets without using additional formulas outside the calculation program, which simplifies and speeds up the search for the final system. The selection is based on the study of the graphs of the modules of tangential and normal components of magnetic induction, followed by the determination of the width of the sputtering zone, the extremes of each component of magnetic induction. The results obtained are compared with the specified tolerances and limitations. The result of the work was to obtain the necessary parameters of thirty-six subsystems of three different configurations, the dependence of the characteristics on the thickness of the magnetic core when it was added to the MSS and the relationship of the indicators on the multiplicity of magnets in the magnetic trap. In the conclusion of the article, the regularities of changes in various trap criteria depending on the configuration are formulated, the efficiency of increasing the number of magnets in the system and the thickness of the magnetic core is compared, the optimal subsystem of the proposed ones is determined.
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Petrushina, A. A., A. A. Abrashov, N. S. Grigoryan, et al. "Protective and Anti-icing Superhydrophobic Coatings on AA5056 Aluminum Alloy." Practice of Anticorrosive Protection 29, no. 1 (2024): 7–19. https://doi.org/10.31615/j.corros.prot.2024.111.1-1.
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The issues of applying superhydrophobic coatings to the surface of metals, metal products and structures are considered. This is relevant, for example, for anti-icing protection of vehicles (airplanes, ships), power lines, buildings and structures for various purposes. In these cases, superhydrophobic coatings perform the function of ice-phobic coatings. Superhydrophobic coatings also help increase the wear resistance of metal products. This work proposes a method for increasing the wear resistance of superhydrophobic coatings through the preliminary application of an adhesive sublayer using various passivating solutions. Over the course of this work, it was found that superhydrophobic coatings with a Ti-Zr-containing sublayer have the highest abrasion resistance. The results of polarization measurements showed that the application of an adhesive sublayer also improves the protective ability of superhydrophobic coatings. The increase in protective ability was also confirmed by salt spray tests. The time until the appearence of the first signs of corrosion increased from 140 to 430 hours. During the work, two technique for determining the adhesion of ice to an aluminum surface were compared. The first technique was based on the parallel “tearing out” of a rod from the ice mass. The second technique is based on the perpendicular pulling of an of aluminum disc out of the ice mass located in the cylinder. It has been shown that when ice is detached from a surface with identical coatings, the adhesion values obtained using different methods differ: with normal detachment, the adhesion values are always lower. Obviously, this is due to the fact that during normal detachment, only the adhesion of ice to the superhydrophobic surface is determined, and during tangential separation, an additional contribution is made by the mechanical engagement of ice with surface protrusions and an increase in the force of ice pressure on the rod, resulting from the expansion of ice during freezing water. The normal tear-off method is considered more relevant.
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Stenull, Olaf, and Tom C. Lubensky. "Director Fluctuations in Two-Dimensional Liquid Crystal Disclinations." Crystals 12, no. 1 (2021): 1. http://dx.doi.org/10.3390/cryst12010001.
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We present analytical calculations of the energies and eigenfunctions of all normal modes of excitation of charge +1 two-dimensional splay (bend) disclinations confined to an annular region with inner radius R1 and outer radius R2 and with perpendicular (tangential) boundary conditions on the region’s inner and outer perimeters. Defects such as these appear in islands in smectic-C films and can in principle be created in bolaamphiphilic nematic films. Under perpendicular boundary conditions on the two surfaces and when the ratio β=Ks/Kb of the splay to bend 2D Frank constants is less than one, the splay configuration is stable for all values μ=R2/R1. When β>1, the splay configuration is stable only for μ less than a critical value μc(β), becoming unstable to a “spiral” mixed splay-bend configuration for μ>μc. The same behavior occurs in trapped bend defects with tangential boundary conditions but with Ks and Kb interchanged. By calculating free energies, we verify that the transition from a splay or bend configuration to a mixed one is continuous. We discuss the differences between our calculations that yield expressions for experimentally observable excitation energies and other calculations that produce the same critical points and spiral configurations as ours but not the same excitation energies. We also calculate measurable correlation functions and associated decay times of angular fluctuations.
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MACCHI, A., H. RUHL, and F. CORNOLTI. "Laser absorption and fast electron transport in deformed targets." Laser and Particle Beams 18, no. 3 (2000): 375–79. http://dx.doi.org/10.1017/s0263034600183041.
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The effect of surface deformations on laser absorption and transport in overdense plasma targets is investigated with 2D Vlasov simulations. Fractional absorption increases strongly with the deformation depth and scales weakly with density or intensity. Fast electrons generated in the skin layer have high tangential velocity directed toward the deformation center. In the case of a single, smooth deformation, they may be collimated by magnetic fields into a single jet which penetrates deeply into the plasma. Small-scale surface corrugations are able to destroy the collimation of a single jet leading to multiple jets or diffuse electron sprays.
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Madurasinghe, M. A. D., and E. O. Tuck. "Ship bows with contiunous and splashless flow attachment." Journal of the Australian Mathematical Society. Series B. Applied Mathematics 27, no. 4 (1986): 442–52. http://dx.doi.org/10.1017/s0334270000005063.
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AbstractIn two-dimensional bow-like flows past a semi-infinite body, one must in general expect a free-surface discontinuity, in the form of a splash or spray jet. However, there is numerical evidence that special body shapes do exist for which this splash is absent. In this study, we first establish conditions on the geometry of the bow in order that it should be splash-free at zero gravity, by solving the mathematical problem exactly. We then obtain solutions for finite non-zero gravity, by solving a non-linear integral equation numerically. A class of splashless body geometries with a downward directed segment at the extreme of the bow, to which the free surface attaches tangentially, is demonstrated in detail.
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Yan, Linbo, Boshu He, Xiaohui Pei, Chaojun Wang, Min Yang, and Jingge Song. "Research on Retrofit Schemes for Reheat Steam Underheating and Excessive Desuperheater Spray for a 600 MW Tangentially Coal-Fired Boiler." Energy & Fuels 26, no. 9 (2012): 5804–20. http://dx.doi.org/10.1021/ef3009986.
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