Influence of Particle Size Distribution on the High-Speed Flow of Gas-Solid Suspensions in a Pipe

1969 ◽  
Vol 184 (3) ◽  
pp. 67-76 ◽  
Author(s):  
F. R. Mobbs ◽  
H. M. Bowers ◽  
D. M. Riches ◽  
B. N. Cole
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Pressure Distribution ◽  
Size Distribution ◽  
High Speed ◽  
High Speed Flow ◽  
Photographic Technique ◽  
Speed Flow ◽  
Predicted Values ◽  
Experimental Values

Experiments on the flow of air-solids mixtures through long straight lengths of brass and nylon pipe, under choking conditions, are described. The powders conveyed are polystyrene, silica, and steel shot. Experimentally determined pressure distribution curves are used to compute the variation of gas and solids, velocities, and temperatures along the pipes, taking into account the size distribution of each powder. The predicted values of gas and solids velocities are compared with experimental values obtained by pitot tube traversing, and a highspeed photographic technique, respectively.

Hydrodynamics of Multiple Size Particles in a Liquid Fluidized Bed Classifier

2003 ◽  
Author(s):  
Dinesh Gera ◽  
Madhava Syamlal ◽  
Thomas J. O’Brien
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Volume Fraction ◽  
Fluid Model ◽  
Operating Conditions ◽  
Particle Sizes ◽  
Two Fluid Model ◽  
Predicted Values

A two fluid model is extended to an N-phase, multi-fluid model, in which each particulate phase represents a collection of particles with identical diameter and density. The current N-phase model is applied to a fluidized bed classifier with six different particle sizes to investigate the effects of different operating conditions—fluidizing liquid flow rate, feed voidage, and particle size distribution in the feed stream—on the particle size distribution inside the classifier and the discharge streams. The predicted volume fraction of different particle sizes is compared with the experimental data reported by Chen et al. (2002) for two columns, 191 mm and 292 mm in diameter, each having different geometries and containing glass beads of different sizes fluidized with water. A fairly good agreement is observed between the measured and predicted values for mono- and poly-dispersed systems.

scholarly journals Preparation of IC21 Spherical Powders by PREP Process

2021 ◽  
Vol 2101 (1) ◽  
pp. 012055
Author(s):  
Qingxiang Wang ◽  
Zhu Zhen ◽  
Shujin Liang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
High Speed ◽  
Distribution Data ◽  
Powder Particle Size ◽  
Rotating Electrode ◽  
Composition Segregation ◽  
Result Show ◽  
Chemical Contents

Abstract The IC21 spherical powders with main content of Ni3Al were successfully manufactured by the high speed plasma rotating electrode process (HS-PREP). The powders particle size distribution fitted the mixed spraying model well. The chemical contents changes after melting were detected. The microstructure of the IC21 powders was formed by cellular crystal on the surface and dendrite inside, which was a typical PREP powder. The morphologies and properties of the irregular powders were also analyzed which indicated that the composition segregation and oxides inclusion of the electrode were the main reason for the formation. However, its proportion was less than 0.5%, which would not affect the additive manufacturing. The fundamental powder particle size distribution data for different rotating speeds was measured. The morphology and properties result show that the PREP could support qualified IC21 spherical powders with significant powder yields.

Effect of Process Parameters on the Particle Size Distribution of Paclitaxel Nanocrystals

2020 ◽  
Vol 12 (2) ◽  
pp. 137-146
Author(s):  
Gannimitta Arvind ◽  
Srinivas Prathima ◽  
Atla Venkateshwar Reddy
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Response Surface ◽  
Size Distribution ◽  
Process Parameters ◽  
Physicochemical Characteristics ◽  
Precipitation Method ◽  
Influence Of Process Parameters ◽  
Predicted Values ◽  
Two Phases

The main intention of this work was to study the effect of process variables on the particle size distribution of paclitaxel nanocrystals. Paclitaxel nanocrystals were prepared by using anti-solvent precipitation method. Box Behnken design was used to optimize the process parameters including the Ratio (v/v) of two phases (A), Ulatrasonication time in min (B) and Surfactant concentration (%w/v) (C). A response surface methodology comprising 17 runs was carried out to optimize the nanocrystal formulation of paclitaxel. Two dependent variables particle size and polydispersity index (PDI) were identified as responses. Polynomial equations and response surface curves were used to relate the dependent and independent variables. The optimization model predicted a mean particle size of 147.653 nm and PDI of 0.1706 with A, B and C levels of 5, 15 min and 0.03% w/v respectively. The observed values were in close agreement with the predicted values. The optimized batches of nanocrystals were analyzed by FTIR, DSC and XRPD techniques. The optimized batch revealed irregular morphology as assessed by transmission electron microscopy and was crystalline as determined by thermal analysis and XRPD studies. Paclitaxel nanocrystals exhibited a considerable increase in solubility as well as dissolution rate in comparison with the pure drug. The present work thoroughly explored the influence of process parameters on the physicochemical characteristics of the produced drug nanocrystals.

scholarly journals A Study on the Air Cavity under a Stepped Planing Hull

2019 ◽  
Vol 7 (12) ◽  
pp. 468 ◽  
Author(s):  
Dongmei Yang ◽  
Zhiyuan Sun ◽  
Yi Jiang ◽  
Zeyang Gao
Keyword(s):  
Flow Field ◽  
Pressure Distribution ◽  
High Speed ◽  
General Procedure ◽  
Shape Evolution ◽  
High Speed Flow ◽  
Air Cavity ◽  
Speed Flow ◽  
Wetted Area ◽  
Volume Method

Based on the FVM (finite volume method) numerical method, the flow field around the stepped planing hull in Taunton series was simulated. According to the general procedure of numerical uncertainty analysis, the numerical uncertainty in the high-speed flow field simulation of the stepped planing hull was discussed. Combined with the wave-making characteristics of the hull, the generation mechanism, shape evolution of air cavity, and the pressure distribution characteristics under the influence of the cavity, focuses on the variation of the flow around the stepped planing when the hull is in the triangle planing stage. Numerical results suggest that, as the air cavity enlarges, the cover rate of the air cavity can rise up to 77.8% of the whole wetted surface of the planing hull bottom. While, in the triangle planing stage, there is additional wetting at the aft bilge, which leads to the decrease of the air cavity rate and the increase of the wetted area. At the same time, the pressure distribution concentrates to the center of gravity.

Printing of Ultrathin Nanoparticulate Indium Tin Oxide Structures

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000092-000102
Author(s):  
Moritz Wegener ◽  
Dieter Spiehl ◽  
Florian Mikschl ◽  
Xinxin Liu ◽  
Andreas Roosen
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Inkjet Printing ◽  
Indium Tin Oxide ◽  
High Speed ◽  
Organic Additives ◽  
Glass Substrates ◽  
Printing Processes

This contribution focusses on three printing techniques: inkjet printing, flexographic printing and gravure printing for the manufacture of ITO structures based on nanoparticular ITO inks. The quality and stability of nanoparticular inks depends mainly on the dispersing step and is reflected by the achieved particle size distribution. The particle size distribution of the ITO inks has a distinct influence on the optical and electrical properties of the deposited ITO structures. The optimization of nanoparticular ITO inks concerning rheological behavior, wetting behavior and resulting material performance is presented. Inkjet printing was used as a low speed method to manufacture structures in the range of 30 μm. It is shown how coffee-staining, a frequently arising problem in inkjet printing, can be prevented by different strategies. Nanoparticular ITO structures with layer thicknesses clearly below 1 μm were printed. Gravure and flexography printing are well-established industrial printing processes with printing speeds above 100 m/min. These high-speed printing processes were used to print structures on PET film and glass substrates. Different solvents, e.g., water and ethanol, solvent compositions and binder types were varied to optimize the resulting ITO structures. The printed structures in the range of 10 to 2000 μm with thicknesses down to 1 μm were evaluated concerning surface topography and electrical conductivity. The high inter-grain porosity and the used organic additives limit the electrical conductivity of nanoparticulate ITO structures. To further improve their electrical conductivity laser post-treatment of printed ITO structures was performed.

scholarly journals Stability, Microstructure, and Rheological Properties of CaCO3 S/O/W Calcium-Lipid Emulsions

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2216
Author(s):  
Jie Zhang ◽  
Gongwei Li ◽  
Duoxia Xu ◽  
Yanping Cao
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Particle Size Distribution ◽  
Soybean Oil ◽  
Size Distribution ◽  
High Speed ◽  
Mean Square Displacement ◽  
Suspension Stability ◽  
Liquid Food ◽  
The Stability

Calcium carbonate (CaCO3) is a commonly used fortified calcium, but poor suspension stability and easy precipitation seriously limited its food processing and products application. The formation of CaCO3 loaded microparticles based on the form of solid/oil/water (S/O/W) emulsion is a promising method to improve the dispersion stability of CaCO3 in liquid food. In this study, CaCO3, soybean oil, and sodium caseinate (NaCas) were used as the solid, oil, and W phase, respectively. The fabrication involved two steps: the S/O emulsion was prepared by adding CaCO3 into soybean oil by magnetic stirring and high-speed shearing, and then put the S/O crude emulsion into NaCas solution (W phase) to obtain S/O/W emulsion by high-speed blender. The particle size distribution, zeta potential, stability of the microsphere, infrared spectral analysis, and XRD of the S/O/W calcium-lipid microsphere were explored. The stability and rheological mechanism of S/O/W calcium-lipid emulsion were investigated by combining the microstructure, shear rheological, and microrheological properties. It was found that the emulsion particles have more uniform particle size distribution and no aggregation, and the stability of the emulsion was improved with increasing the content of NaCas. The mean square displacement (MSD) curve and solid-liquid equilibrium (SLB) value of S/O/W emulsion increased with the increase in NaCas concentration, and the viscosity behavior is dominant. The results of confocal laser microscopy (CLSM) and cryo-scanning electron microscopy (Cryo-SEM) showed that the three-dimensional network structure of S/O/W emulsions was more compact, and the embedding effect of calcium carbonate (CaCO3) was slightly improved with the increase in NaCas concentration. According to infrared spectrum and XDR analysis, the addition of CaCO3 into the emulsion system caused crystal structure distortion. This study provides a reference for solving the dispersibility of insoluble calcium salt in liquid food.

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