Papers by Keyword: Atomization

Abstract: Technological progress introduces new ideas and methods that eventually end up being in another technology. One technology can not provide a solid ground for the future and, thus, technologies intervene with each other. A combination of technologies allows the achievement of greater application in different fields and areas and better performance and functionality. The Internet of Things is not a new idea, but due to the improvement of other technology can be used in different industries to achieve better optimization. Internet of Things can be found in different industries, but the focus of this work is in the field of robotics. Therefore, the following work will try to illustrate the use of technology in this field. A brief definition of the Internet of Things will be covered. The application of the technology in robotics will be outlined with its future perspectives. The advantages and drawbacks of the Internet of Things in the field of robotics will be discussed at the end.

Abstract: Selective laser melting (SLM) is one of the additive manufacturing technologies that allows us to produce complex shape metallic objects from powder feedstock. Al-alloys are very promising materials in selective laser melting. In this paper, atomized metal powders of various aluminum alloys are investigated: 1) deformable alloys АК4, АК6; 2) cast alloys АК9ph, АК12; 3) deformable hardened alloy D16. As a part of the work, the particle shape, particle size distribution and technical characteristics of the powders were investigated, and also the compliance of materials with the requirements of additive technologies (SLM) was determined.

Abstract: In microlubrication, effective spray cooling is generally dependent on the atomization process. Air assisted atomizer is commonly used in many industrial applications because even at low-pressure fuel or coolant supply, it can create a fine spray formation. Viscosity force resists the deformation of liquid ligaments into a droplet. This increase in viscosity creates a bigger droplet size. If the density of the coolant is more, it will resist the acceleration and results in a bigger droplet. Properties of coolant such as viscosity, density, and surface tension are important and will affect the droplet size. Hence, for effective microlubrication, the performance study of atomization is important. In this paper, computational fluid dynamics (CFD) is used to study atomization characteristics of biodegradable coolant castor oil and AccuLube-2000 at flow rate 150 ml/hr to 60 ml/hr. This paper focuses on the effect of coolant properties like viscosity and density on the droplet size and discrete phase model concentration. In this work, the CFD atomization is studied using a discrete phase model and a Realizable k-ϵ turbulent flow model. Numerical simulation shows that the droplet size of the castor oil is more than AccuLube-2000. Also, for a higher flow rate, the area near the nozzle had a very uneven concentration of sprayed particles. However, the concentration was more even as the spray went farther away from the nozzle.

Abstract: In this paper, we investigated the porosities and their formation mechanism in the nickel-base superalloy powders, which were prepared by electrode induction melting argon atomization and divided into four particle size ranges: d＜60μm, 60μm≤d＜120μm,120μm≤d＜180μm, and d≥180μm. Firstly, the distribution of porosities in the powder were observed by Zeiss electron microscope. Secondly, the number and size of porosities in different particle size range were counted. Finally, the formation mechanism of the porosity was analyzed in details. The results show that the porosities are mainly distributed at the edge and center of the powders, and the size increases with the increase of the powder size. the porosity varies from a few microns to dozens of microns. the biggest pore size in the powder is approximately 120μm.There are no obviously porosities found in powders when their diameters are less than 60μm. While the porosity appeared as the powder diameter is more than 60μm. In addition, the proportion of the powder with porosities also increases with increasing powder size. When powders size is more than 180μm, the proportion of the powder with porosities reached about 91%. In general, the formation of porosities in powders are mainly ascribed to two reasons. the first one is a portion of argon was enclosed by the metal films during the spheroidization; the second one is the metal droplets uneven shrinkage during the solidification.

Abstract: This article is devoted to the research of powders for the additive technologies made by EOS Company. Their analysis showed that the powders’ average diameter is about 30 microns. Powders are received by method of electrospark dispersion. The X-ray diffraction and metallographic analysis of these powders is presented.

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.

Abstract: Atomization quality of liquids has a great importance on the performance of combustion engines. In this study the internal flow phenome of pressure swirl atomizer is investigated by using numerical method. The design of swirl atomizer is performed based on the requested atomizer characteristics which are sauter mean diamer (SMD), spray cone angle and break up length. Prediction and understanding of liquid film dynamics in the atomizer inside are the fundamental ways to explore atomizer performance. The purpose of this study is to estimate the air core size and film thickness in pressure swirl atomizer by setting single phase numeric computations. This article concludes that the CFD validated swirl atomizer design can be achieved with the lower computational cost using stream function methodology.

Abstract: Atomization and fuel-air mixing is an important process in diesel combustion. It directly affects the combustion and emission of diesel engine. Optical technique has the advantage of being unobtrusive in nature when compared to other technique. nanospark unit that has spark duration of 30ns was used as a lightsource to capture high resolution spray image using still film camera. The very short duration of the spark freeze the fast movement of the spray droplet, and sharp image of fuel droplet to be successfully captured by the camera, and then analyzed for sizing and spatial distribution. In addition, by using a more elaborate optical setup, dual image of the same spray can be captured, with a very short time interval between each of them. This provides the means to study dynamic behaviors of the diesel spray and also the droplets, as the progression of the spray and trajectory and velocity of the droplet can be analyze from these images. With the proposed optical technique and optical arrangement, microscopic detail of the diesel engine spray can be captured. Critical data such as droplet sizing can be extracted from this high resolution image. Furthermore, by introducing a more sophisticated optical arrangement coined dual-nano spark photography method, the droplet dynamic behaviors such as flying angle and velocity can be study.

Abstract: 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.

Abstract: The controlled solution spray process with superior molecular contacting between finely atomized reactants in impinging solution spray reactor was carried out with an objective to develop the nonionic surfactant (Tween-80) mediated coprecipitation protocol for the polymorph selective synthesis of lead chrome (PbCrO₄) nanocrystals. Monoclinic PbCrO₄ nanorods with size in the range of 37.8-51.9 nm at Tween-80 loadings of 2-10 g/L were obtained. The functional group, surfactant adsorption, crystal type, size and morphology of the PbCrO₄ nanocrystals were determined by FTIR, XRD and FESEM analysis.