Papers by Keyword: Atomization

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Authors: Taek Kyun Jung, T.J. Sung, Mok Soon Kim, Won Yong Kim
Abstract: Al-8Fe-2Mo-2V-1Zr alloy powders were prepared by gas atomization and melt spinning method. In melt spinning technique, melt spun ribbons were pulverized by a speed rotor mill to make a powder shape. In order to produce a bulk form, powders were canned and hot extruded in the extrusion ratio of 25 to 1 at 693K. For the gas atomization and hot extrusion processed bulk material, equiaxed grains with the average size of 400 nm and finely distributed dispersoids with their particle sizes ranging from 50nm to 200nm were observed to display a characteristic nano-structured feature over the entire region. For the melt spun and hot extrusion processed alloy, a refined microstructural feature consisting of equiaxed grains with the average size of 200 nm and fine dispersoids with their particle sizes under 50 nm appeared to exhibit a difference in microstructure. Yield strength of the latter alloy was higher than that for the former alloy up to elevated temperatures. The maximum yield strength was measured to about 800 MPa at room temperature for the latter alloy.
765
Authors: Hui Zhang, Zi Feng Ni, Qing Zhong Li
Abstract: In this paper, a kind of alkaline slurry was introduced, in which silica was used as the abrasive, H2O2 was used as the oxidize, glycine was used as the complexing agent, azimidobenzene was used as the surfactant, and borax was used as the pH regulator. The atomization polishing method was used, and the effects of the traditional polishing and atomization polishing were compared. After the atomization polishing, the surface roughness of copper was 7.61 nm and the material removal rate was 188 nm/min; After the traditional polishing, the surface roughness was 15.22 nm and the material removal rate was 236 nm/min. The dosage of polishing slurry used in the atomization polishing is dozens of times less than that in the traditional polishing.
271
Authors: Na Cao, Liang Cao, Chang Cai Han, Qing Xu, Lan Lei, Ji Ye Du, Jun Xue, Zhan Hong Zhang
Abstract: Centrifugal nozzle is an important part of an areoengine in which fuel atomization has strong influence on engine performance. For investigating the fuel spray characteristics, a promising method named off-axis particle holographic measuring system is used here. Characteristics of the nonevaporating spray ejected from a new type of centrifugal nozzle which would be used in the near future are obtained under various injection conditions. By automatic analysis of the holographic reconstructed droplets images, a hollow-cone shape spray with most droplets concentrated in the surface of the cone is observed, and the spray cone angle, droplet sizes and their spatial locations in concerned region are obtained quantitativly. In the near region of the nozzle exit, droplets show greater SMD value, while at a certain distance from the nozzle, the droplets SMD differences become unconspicuous which shows a better atomization. These informations are helpful to understand characteristics of the centrifugal nozzle and offer a database for validating the spray simulation code.
846
Authors: Feng Che Tsai, Shie Chen Yang, Tsuo Fei Mao, Chi Jung Chen, Shiou Shen Liou
Abstract: This Study Examined the Performance of Abrasive Jet Polishing (ajp) on Skd61 Mold Surfaces Using Wax-coated Sic Abrasives Fabricated by Gas Atomization. Comparison of Surface Quality Achieved Reveals Significant Surface Roughness Reduction by Wax-coated Abrasives. the Wax Coating Not only Covers Most of the Sharp Ends of the Abrasive, Thus Making Smooth the Abrasive Surface; it Being Elastic Also Provides a Cushioning Buffer. these Two Features Contribute to Ameliorate the Direct Impact of Heavy Peening, Thus Preventing Surface Hardening, Superficial Embedment or Deep Scratches. Moreover, Compound Additives Including Water Wax and Water Were Added to the Wax-coated #3000 Sic Abrasives at a Mix Proportion of 500: 1000: 1500 (water Wax: Wax-coated Sic: Water) for Polishing Mold Surfaces of Different Forms. Results Show that the Compound Additives Provide Addition Cushioning Effect and Facilitate the Sliding and Grinding of Abrasives, Resulting in Fine Polishing and Good Surface Quality. the Reflection Property of Micro-groove Was much Enhanced by Ajp Using Wax-coated #3000 Sic Abrasives with the Compound Additives.
2153
Authors: E.M. Mazzer, Claudio Shyinti Kiminami, P. Gargarella, R.D. Cava, L.A. Basilio, C. Bolfarini, W.J. Botta, J. Eckert, T. Gustmann, S. Pauly
Abstract: Shape memory alloys (SMAs) are a class of material that undergoes a reversible shape change after a plastic deformation. The recovery of the original shape is possible due to a structural transformation upon heating to a critical temperature. The shape memory effect is related to a martensitic-austenitic transformation from a phase with a low symmetry (martensite) to a high-temperature phase (parent phase) [1]. Cu-based shape memory alloys have the advantage of large thermal and electrical conductivities and the system Cu-Al-Ni alloys are quite attractive due to better stabilisation against aging phenomena [2].
343
Authors: Li Jun Fang, Yan Chao Chang
Abstract: A study was performed of the atomization feature of liquid-column tower. It was found that the broken droplets can be classified into three types which called convex,twisted and broken. Proposed that the atomization process of liquid column tower consist of impact atomization and run into a wall atomization. Analysis of the atomization mechanism of the two processes, and the run into a wall atomization have droplet rebound,expand,splash stages. In addition ,the high degree of atomization of theoretical formula was amended. After modified, the theoretical and actual values are basically consistent.
1795
Authors: Lydia Achelis, Volker Uhlenwinkel, S. Lagutkin, Sh. Sheikhaliev
Abstract: An update and the latest results on molten metal atomization using a Pressure-Gas- Atomizer will be given. This atomizer combines a swirl-pressure atomizer, to generate a liquid hollow cone film and a gas atomizer to atomize the film and/or the fragments of the film. The paper is focused on powder production, but this atomization system is also applicable for deposition purposes. Different alloys (Sn, SnCu) were atomized to study the characteristics of the Pressure- Gas-Atomizer. The powders produced were analyzed by laser diffraction and image processing. Among other parameters, the molten metal mass flow (~140 – 200 kg/h), the gas mass flow and the atomizer design were varied. The results include the effects of these variances on particle size and particle shape.
13
Authors: Daniel Rodrigues, C.A.F.R. Filho, J.B. Ferreira Neto, J. Kashiwaba, Lucio Salgado, P. Nogueira
182
Authors: Gökhan Tuccar, Göktürk Memduh Özkan, Kadir Aydın
Abstract: Atomization of liquid fuels is very important topic for combustion studies since it enhances air/ fuel mixing process and therefore ensures perfect combustion. With today’s common diesel injectors, fuel is directly injected into the combustion chamber with extremely high pressures which exceed 1300 bar in order to obtain perfect atomization. However, these high injection pressures unfortunately create some problems in the injection system such as cavitation erosion which may lead to mechanical failure. Introducing of air into the injector prior to combustion will increase fuel atomization, provide more complete combustion, enhance fuel economy and results in lower engine emissions. The aim of this study is to investigate atomization behaviour of a newly introduced diesel engine which mixes air and fuel prior to combustion chamber.
826
Authors: Vádila Giovana Guerra, M.A.F. Daher, M.V. Rodrigues, José Antônio Silveira Gonçalves, José Renato Coury
Abstract: The Venturi scrubber, equipment frequently used in the removal of particles from gases, is constituted basically by a duct with a convergent section followed by a constriction, or throat, and a divergent section. A liquid, usually injected in the throat, is atomized by the flowing air at high speed. The formed droplets act as collectors of particles from the gas. The size and the size distribution of the droplets inside the equipment are therefore of great importance in the equipment performance. In the present work, the liquid jet penetration is visualized and the study of the droplet formation in a rectangular Venturi is carried out. The liquid injection is made through multiple orifices and the interaction of multiple jets is taken into account. In the experimental tests, the gas velocity in the throat, the liquid flow rate and the number of orifices for liquid injection were varied. A Malvern Spraytec aerosol analyzer was used for measuring of the droplet size and size distribution. The results showed that the liquid jet penetration influences significantly the size of the formed droplet.
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