Nucleation During the Solidification of Atomized Droplets Catalyzed by Spherically-Shaped Oxide Particles

1986 ◽  
Vol 80 ◽  
Author(s):  
Matthew R. Libera ◽  
Gregory B. Olson ◽  
John B. Vander Sande
Keyword(s):  
Oxide Particle ◽  
Rare Earth Oxide ◽  
Pure Liquid ◽  
Liquid Droplets ◽  
Particle Size Distributions ◽  
Pure Liquid Iron ◽  
Droplet Sizes ◽  
Oxide Substrate ◽  
Oxide Particles ◽  
Substrate Particle

AbstractNucleation temperatures are calculated for the case of solidification in atomized metal droplets where spherical substrate particles act as nucleation catalysts. Following the method of Fletcher, the effect of substrate size on catalytic potency is illustrated, and the model is applied to the nucleation of bcc solid from pure, liquid iron containing oxide substrate particles as catalysts. Supercooling data from the literature are used to determine wetting angles for alumina, silica, and rare-earth oxide. Oxide particle-size distributions are then used to predict the supercooling behavior of atomized liquid droplets based on the probability that a given size of droplet will contain a particular size of substrate particle. A transition size regime is found separating droplet sizes undergoing very small and very large supercoolings, respectively. This is discussed in terms of the types and number densities of inclusions present during atomization of the melt.

Drift of Droplets from Air-Induction Nozzles

2019 ◽  
Vol 62 (6) ◽  
pp. 1683-1687
Author(s):  
Scott L. Post
Keyword(s):  
Aerodynamic Drag ◽  
Numerical Models ◽  
Liquid Sheet ◽  
Pure Liquid ◽  
Liquid Density ◽  
Liquid Droplets ◽  
Pesticide Application ◽  
Spray Density ◽  
Droplet Sizes ◽  
Moving Liquid

Abstract. For more than 20 years, air-induction or air-inclusion (AI) nozzles have had increased use for pesticide application due to their drift reduction capabilities. The pressure drop created by the pre-orifice and the venturi chamber results in a slower-moving liquid sheet exiting the main orifice, which in turn results in larger droplet sizes, which are less prone to drift. However, two additional factors somewhat mitigate the advantage of larger droplets from AI nozzles: the lower initial spray jet momentum from AI nozzles (compared to standard nozzles of the same flow rating at the same pressure) means that droplets from AI nozzles are more affected by lateral crosswind, and the lower effective liquid density of droplets from AI nozzles due to the presence of air inclusions means that AI droplets are more affected by aerodynamic drag than pure liquid droplets of comparable sizes from standard nozzles. In this work, theoretical and numerical models are developed to quantify these effects and develop tools for accurate drift prediction from sprayers using AI nozzles. The reduction in spray density due to the presence of air inclusions is in the range of 12% to 36%. This reduction in density affects the aerodynamic drift of the spray droplets, with the result that a droplet with 30% air inclusions would have the drift characteristics of a normal droplet with 20% smaller diameter. HighlightsSprays from air induction (AI) nozzles typically contain 12% to 36% air inclusions by volume.A droplet with 30% air inclusions would have the same drift characteristics as a water droplet of 20% smaller diameter.An analytical model is developed to predict the drift distances of small droplets. Keywords: Air induction, Droplet size, Nozzles, Pesticides, Sprayers.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

scholarly journals Role of rare earth oxide particles on the oxidation behaviour of silicon carbide coated 2.5D carbon fibre preforms

Open Ceramics ◽  
2020 ◽  
Vol 2 ◽  
pp. 100018
Author(s):  
T.S.R.C. Murthy ◽  
Lucas Reeman ◽  
Ji Zou ◽  
Vinothini Venkatachalam ◽  
Ben Baker ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Rare Earth ◽  
Carbon Fibre ◽  
Rare Earth Oxide ◽  
Oxidation Behaviour ◽  
Oxide Particles

scholarly journals One-Step Synthesis of Copper and Cupric Oxide Particles from the Liquid Phase by X-Ray Radiolysis Using Synchrotron Radiation

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Akinobu Yamaguchi ◽  
Ikuo Okada ◽  
Takao Fukuoka ◽  
Mari Ishihara ◽  
Ikuya Sakurai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Synchrotron Radiation ◽  
Cupric Oxide ◽  
Oxide Particle ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
One Step ◽  
Oxide Particles

The deposition of copper (Cu) and cupric oxide (Cu4O3, Cu2O, and CuO) particles in an aqueous copper sulfate (CuSO4) solution with additive alcohol such as methanol, ethanol, 2-propanol, and ethylene glycol has been studied by X-ray exposure from synchrotron radiation. An attenuated X-ray radiation time of 5 min allows for the synthesis of Cu, Cu4O3, Cu2O, and CuO nano/microscale particles and their aggregation into clusters. The morphology and composition of the synthesized Cu/cupric oxide particle clusters were characterized by scanning electron microscopy, scanning transmission electron microscopy, and high-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy. Micro-Raman spectroscopy revealed that the clusters comprised cupric oxide core particles covered with Cu particles. Neither Cu/cupric oxide particles nor their clusters were formed without any alcohol additives. The effect of alcohol additives is attributed to the following sequential steps: photochemical reaction due to X-ray irradiation induces nucleation of the particles accompanying redox reaction and forms a cluster or aggregates by LaMer process and DLVO interactions. The procedure offers a novel route to synthesize the Cu/cupric oxide particles and aggregates. It also provides a novel additive manufacturing process or lithography of composite materials such as metal, oxide, and resin.

Gettering and Gettering Stability of Metals at Oxide Particles in Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
R. Falster ◽  
Z. Laczik ◽  
G. R. Booker ◽  
A. R. Bhatti ◽  
P. Török
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Particle Number ◽  
Oxide Particle ◽  
Internal Oxide ◽  
Transmission Electron ◽  
Metal Type ◽  
Infra Red ◽  
Oxide Particles ◽  
Thermal Stability Of

ABSTRACTSeveral aspects of metal gettering at internal oxide particle sites in Cz Si have been studied by ‘haze tests’, scanning infra-red microscopy (SIRM) and transmission electron microscopy (TEM). Haze tests indicated that complete gettering of Cu, Ni, Co and Pd can occur even when the amount of oxygen precipitated is below the detectable limit. TEM showed that the gettering of Cu, Pd and Ni proceeds by one of three different self-perpetuating mechanisms involving oxide particles and associated dislocations, the particular mechanism depending on the oxide particle size and the metal type. Haze tests and SIRM showed that for Cu and Ni there were minimum oxide particle number densities for effective gettering, and also maximum oxide particle number densities above which the additional oxide particles played no role in the gettering. These number densities depended on the metal type and specimen cooling rate. For all of these gettering behaviours, mechanisms are suggested to explain the results. The SIRM was also used to investigate for Cu and Ni the thermal stability of the gettering sites and the precipitated metals. The results showed that during repeated heat treatments the gettering occurs by a dynamic process.

PRESSURE–VOLUME CURVES IN ISOLATED ATELECTATIC RAT LUNGS AFTER ALUMINUM OXIDE MICROPARTICLE INHALATION

1963 ◽  
Vol 41 (1) ◽  
pp. 1257-1265 ◽  
Author(s):  
E. Robillard ◽  
Y. Alarie
Keyword(s):  
Guinea Pig ◽  
Aluminum Oxide ◽  
Normal Control ◽  
Oxide Particle ◽  
Aluminum Particles ◽  
Aluminum Oxide Particle ◽  
Rat Lungs ◽  
Particle Inhalation ◽  
Oxide Particles ◽  
Volume Pressure Curves

Volume–pressure curves obtained from isolated atelectatic rat lungs under normal control conditions were compared with those obtained from lungs of animals previously exposed to inhalation of submicronic aluminum oxide particles for various periods of time. A dilating effect was recorded in rat lungs after aluminum oxide particle inhalation contrasting with the constricting effect reported by many authors in guinea pig, dog, cat, and man. Inhalation of fine aluminum particles before or after inhalation of sympathomimetic aerosol resulted in a more intense dilatation. The constricting effect of carbachol was antagonized by prior inhalation of fine aluminum oxide dust and enhanced when the order of inhalations was reversed.

Modeling the Effects of Various Liquid Droplet Sizes in Acoustic Deliquification Techniques

2021 ◽  
Author(s):  
Eiman Al Munif ◽  
Ahmed Alrashed ◽  
Kanat Karatayev ◽  
Jennifer Miskimins ◽  
Yilin Fan
Keyword(s):  
Fluid Dynamics ◽  
Natural Gas ◽  
Computational Time ◽  
Liquid Droplets ◽  
Gas Wells ◽  
Air Velocity ◽  
Liquid Loading ◽  
Artificial Lift ◽  
Tool Surface ◽  
Droplet Sizes

Abstract Liquid loading is a major challenge in natural gas wells. Enhancing the production in liquid loading natural gas wells using an acoustic liquid atomizer tool is proposed as a possible artificial lift method. The effect of different droplet sizes on the transport efficiency and the performance of the proposed technique during production are studied using Computational Fluid Dynamics (CFD) simulation. Also, the liquid behavior and fluid dynamics after applying the atomization mechanism are reviewed. In the model, the tool is placed axially in the middle of the gas/air flowing wellbore. To reduce computational time, the tool and pipe are cut symmetrically. The pipe diameter is 4 in, and the four injectors diameters are each 0.04 in. The orientation of the injectors is set to 90° with the sprayers facing sideways, while water liquid droplets are injected from the tool surface into the air flow at angles from 45° to the flow direction. Unstructured hybrid mesh is used to allow the cells to assemble freely within the complex geometry. Sensitivity tests were conducted with droplet sizes ranging between 30-300 µm. The CFD results showed that water liquid droplets of size 30 µm followed the pathway along the tool surface due to the low mass of the droplets and high air velocity. This phenomenon is called wall impingement and occurs where the droplets are very small and clustering on the wall. The 200 and 300 µm water liquid droplets kept their inertial high chaotic movements in all directions within the computational fluid domain due to the increased weight of the droplets. These larger sized droplets withstand the backpressure from high turbulent air velocity and tend to keep their inertial turbulent movement. This research presents a set of CFD results to further evaluate acoustic atomization as a possible artificial lift technique. This technique has never been commercially applied in the oil and gas industry, and continued evaluation of such methods is a vital addition to the industry as it brings the potential for new lower cost artificial lift technologies. If completely developed, this technique can bring a cost-effective solution compared to conventional artificial lift methods.

Molecular Dynamics Simulations of Damage Cascades Creation in Oxide-Particle-Embedded Fe

2017 ◽  
Author(s):  
A. M. Mustafa ◽  
Zhongyu Li ◽  
Lin Shao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Oxide Particle ◽  
Oxide Dispersion Strengthened ◽  
Atomic Scale ◽  
Scale Modeling ◽  
Alloy Type ◽  
Oxide Particles ◽  
Ods Alloys ◽  
Dynamics Simulations

Oxide-dispersion-strengthened (ODS)alloys have been identified as one promising candidate alloy type for high temperature reactor applications. Understanding irradiation stability of ODS alloys relies on atomic scale modeling such as molecular dynamics simulations. In this study, yttrium and oxygen charges in Y2O3 oxide particles, which are embedded in pure Fe matrix, are optimized to achieve stabilities observed in experiments. Deviation from the optimized charges causes self-explosion and instability of oxide particles. Molecular dynamics simulations further show that under such optimized charge conditions, damage cascade creation and defect developments can be appropriately modeled.

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