scholarly journals Numerical Simulation on Gas-Solid Two-Phase Flow in Horizontal Pneumatic Conveying Pipe Based on DPM Model

2021 ◽  
Vol 2097 (1) ◽  
pp. 012003
Author(s):  
Zihan Guo ◽  
Jun Zhang ◽  
Jinman Huang
Keyword(s):  
Particle Size ◽  
Working Condition ◽  
Particle Sizes ◽  
Pneumatic Conveying ◽  
Lagrange Method ◽  
Two Phase ◽  
Phase Concentration ◽  
Discrete Phase ◽  
Selection Of

Abstract The determination of pipe deposition and optimum conveying velocity in pneumatic conveying has an important impact on conveying efficiency. The Euler-Lagrange method DPM model is used to analyse five different particle sizes and densities of small particles, and the flow pattern in the horizontal pipeline at different particle sizes and densities is derived from the graphs of the maximum discrete phase concentration, particle trajectory and discrete phase concentration distribution for each working condition. The simulation results show that the deposition increases with particle size and density, the optimum conveying speed increases with particle size and density, the larger the deposition, the larger the required conveying velocity. The velocity of 2 m/s can make the particles below 20μm suspended transport, the velocity of 4 m/s allows particles with a particle size of 30μm and a density of 1000 kg/m3 or less to be transported in suspension and 6 m/s allows particles with a density of 2000 kg/m3 or less to be transported in suspension. The aim is to provide a reference for the design of pneumatic conveying systems and the selection of the optimum conveying velocity.

Effects of Particle Size and Method of Milling on Determination of Morphine in Papaver somniferum L. Straw

1982 ◽  
Vol 65 (3) ◽  
pp. 651-654
Author(s):  
Beatriz Ferreira Engelke ◽  
Phillip G Vincent
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
Reproducibility Of Results ◽  
Ball Mill ◽  
Papaver Somniferum ◽  
Particle Sizes ◽  
Morphine Content

Abstract Different particle sizes of blade- and ball-milled poppy straw were separated and analyzed for morphine by high pressure liquid chromatography. Morphine content varied up to 70% among the different size particles. This may account for discrepancies observed in percentages of morphine found among random aliquots. Homogenizing a carefully quartered sample of blade-milled straw by further pulverization in a percussion ball mill 2 min and taking a quartered aliquot for morphine analysis improved the reproducibility of results.

scholarly journals Modelling of Metallic Particle Binders for Increased Part Density in Binder Jet Printed Components

2019 ◽  
Author(s):  
Joseph Roberts ◽  
Peter Green ◽  
Kate Black ◽  
Christopher Sutcliffe
Keyword(s):  
Particle Size ◽  
Critical Radius ◽  
Detailed Knowledge ◽  
Particle Sizes ◽  
Powder Bed ◽  
Beneficial Effects ◽  
Drop Tests ◽  
Maximum Particle ◽  
Packing Efficiency ◽  
Selection Of

Binder jet printed components typically have low overall density in the green state and high shrinkage and deformation after heat treatment. It has previously been demonstrated that, by including nanoparticles of the same material in the binder, these properties can be improved as the nanoparticles can fill the interstices and pore throats between the bed particles. The beneficial effects from using these additive binder particles can be improved by maximising the binder particle size, enabling the space within the powder bed to be filled with a higher packing efficiency. The selection of maximum particle size for a binder requires detailed knowledge of the pores and pore throats between the powder bed particles. In this paper, a raindrop model is developed to determine the critical radius at which binder particles can pass between pores and penetrate the bed. The model is validated against helium pycnometry measurements and binder particle drop tests. It is found that the critical radius can be predicted, with acceptable accuracy, using a linear function of the mean and standard deviation of the particle radii. Percolation theory concepts have been employed in order to generalise the results for powder beds that have different mean particle sizes and size distributions. The results of this work can be employed to inform the selection of particle sizes required for binder formulations, to optimise density and reduce shrinkage in printed binder jet components.

scholarly journals Prediction of Horizontal Pneumatic Conveying of Large Coal Particles Using Discrete Phase Model

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Daolong Yang ◽  
Ge Li ◽  
Yanxiang Wang ◽  
Qingkai Wang ◽  
Jianping Li ◽  
...  
Keyword(s):  
Simulation Method ◽  
Phase Model ◽  
Pneumatic Conveying ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Coal Particles ◽  
Large Particles ◽  
Discrete Phase ◽  
Field Velocity ◽  
Conveying System

The pneumatic conveying focusing on gas-solid two-phase flow plays an important role in a conveying system. Previous work has been conducted in the fields of small particles, where the size was less than 5 mm; however, there are few studies regarding large sizes (>5 mm). In order to predict the horizontal pneumatic conveying of large coal particles, the coupling methods based on the Euler–Lagrange approach and discrete phase model (DPM) have been used for the simulated research. Compared with the experimental results under the same working condition, the particle trajectory obtained by simulation is similar to the particle distribution at the same position in the experiment, and it turns out that the simulation method is feasible for the horizontal pneumatic conveying of large particles. Multifactor simulations are also carried out to analyse the effects of particle size, flow field velocity, solid-gas rate, and pipe diameter on the wall abrasion during horizontal pneumatic conveying, which provides simulation reference and design guide for pneumatic conveying of large particles.

scholarly journals DILUTE PHASE VERTICAL PNEUMATIC CONVEYING OF CORK STOPPERS

2006 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
R. Barbosa ◽  
C. Pinho
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Phase Flow ◽  
Pneumatic Conveying ◽  
Simple Correlation ◽  
Two Phase ◽  
State Region ◽  
Single Pipe ◽  
Cork Stoppers

The pneumatic conveying of cork stoppers is used in the cork processingindustries with equipments designed and built purely on an empirical basis.Experimental studies to characterize this type of pneumatic transportationhave been, so far, oriented towards the study of horizontal conveying processes, either for steady state transportation or for the acceleration zone.However studies were carried out on the determination of the pressure dropon vertical transportation of cork stoppers. Here the experimental apparatusand procedure are described, and the first experimental data that have beenobtained are shown. In consequence a simple correlation for the pressure drop in the steady state region of the conveying pipe is proposed. Thecorrelation is a function of dimensionless parameters used to characterizethe two phase flow under analysis. Three standard stoppers sizes and a single pipe diameter were used in the experiments, all carried out at ambient temperature.

Particle Size Study of Smectite Clays from the City of Pedra Lavrada-PB

2014 ◽  
Vol 775-776 ◽  
pp. 377-382
Author(s):  
Mirtys Allamana Ferreira Cardoso ◽  
Alexsandra Cristina Chaves ◽  
M.M. Dantas ◽  
Isabelle Albuquerque da Silva ◽  
I.D.S. Pereira ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Drilling Fluids ◽  
Particle Sizes ◽  
Smectite Clays ◽  
Significant Difference ◽  
Water Based ◽  
The City

The state of Paraíba disposes of one of the largest deposits of smectites in the country. However, these smectites present in their composition elevated contents of accessory minerals, especially quartz. For these clays to become viable to determine technological use it is necessary the elimination of part of these minerals. The particle size analysis of a soil consists in the determination of the size of the particles that constitute it and their distribution in certain intervals. This work aims to study smectite clays from the city of Pedra Lavrada-PB, through the particle size analyses, for the use in water based drilling fluids. The determination of particle size was made by sieving and laser granulometer. Apparent and plastic viscosities were measured from the samples. The clays were left at rest before the test for periods of 7 and 28 days, with and without deflocculant. It was verified that there was no significant difference in the particle sizes in relation to the resting time of the samples.

Determination of Particle-Size Distribution in GR-S Latexes

1954 ◽  
Vol 27 (4) ◽  
pp. 1051-1060 ◽  
Author(s):  
Alfred Nisonoff ◽  
W. E. Messer ◽  
L. H. Howland
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Light And Electron Microscopy ◽  
Wide Distribution ◽  
Plant Production ◽  
Particle Sizes ◽  
Laboratory Centrifuge ◽  
Made In

Abstract A method based on Stokes' law, involving the use of an ordinary laboratory centrifuge, is described for the determination of particle size distribution in GR-S latexes. It is shown to be valid by tests for reproducibility and by comparison with the results of light and electron microscopy. In applying the method, several unusually fluid high-solids latexes made in the pilot plant were found to be characterized by a wide distribution of particle sizes. Data on various latexes in plant production are reported.

scholarly journals A Two-Fluid Model for High Viscosity Upward Annular Flow in Vertical Pipes

2021 ◽  
Author(s):  
Joseph X. F. Ribeiro ◽  
Ruiquan Liao ◽  
Aliyu M. Aliyu ◽  
Salem K. B. Ahmed ◽  
Yahaya D. Baba ◽  
...  
Keyword(s):  
Fluid Model ◽  
Accurate Determination ◽  
Flow Characteristics ◽  
High Viscosity ◽  
Two Phase ◽  
Friction Factors ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Selection Of

Selection of appropriate friction factors is paramount for accurate prediction of key flow characteristics in gas–liquid two-phase flows. In this work, experimental investigation of vertical air and oil (with viscosities up to 200 mPa s) flow in a 0.060-m ID pipe is reported. Superficial air and oil velocity ranges utilized are from 22.37 to 59.06 m/s and 0.05 to 0.16 m/s respectively. The influence of estimation of interfacial friction factor on accurate determination of film thickness, void fraction and pressure gradient was investigated using a two-fluid model. The results indicated that the two-fluid model is capable of accurately predicting flow characteristics. Further, it reveals that the best performing correlations are the Belt et al. and Ambrosini et al. correlations.

Determination of Particle Size in Latex

1953 ◽  
Vol 26 (2) ◽  
pp. 481-486 ◽  
Author(s):  
E. G. Cockbain
Keyword(s):  
Particle Size ◽  
Sodium Dodecyl Sulfate ◽  
Natural Rubber ◽  
Sodium Dodecyl ◽  
Average Particle ◽  
Particle Sizes ◽  
Sulfate Concentration ◽  
Titration Method ◽  
Dodecyl Sulfate

Abstract The soap titration method of determining average particle sizes in synthetic latexes has been modified so as to make it applicable to natural rubber latexes. The method consists essentially in determining the distribution of an added detergent (sodium dodecyl sulfate) between the rubber and aqueous phases at a pH of approximately 6.0, the total dodecyl sulfate concentration being just sufficient for the formation of micelles in the aqueous phase. The average particle sizes of nine ammoniated latexes have been measured, including centrifuged and electrodecanted concentrates, two clonal field latexes and a sample of latex skim.

Enhanced Low-Pressure Pneumatic Conveyance Using Swirl

2010 ◽  
Author(s):  
Rodrigo Escandon ◽  
Randall D. Manteufel ◽  
Q. Ken Su
Keyword(s):  
Vertical Section ◽  
Experimental System ◽  
Low Pressure ◽  
Phase System ◽  
Pneumatic Conveying ◽  
Two Phase ◽  
Before And After ◽  
Pneumatic Conveyance ◽  
Experimental Values

Two designs for swirl amplification have been considered for pneumatic conveyance in vertical pipes. Both designs have been experimentally evaluated in order to predict their capability. The designs have been compared to other methods of amplification or swirl generation. The motivation for the swirl in pneumatic conveyance is to minimize axial velocity by using multiple swirl amplifications to enhance the transportation for long distances. In this experimental evaluation two swirl amplifiers are considered. The evaluations are done by determining the static pressures before and after the swirl amplifier in the vertical section of an experimental system. This difference in pressure points allowed the determination of length of decay, which is the distance in which this two-phase system travels before a reduction in radial velocity. In the amplifiers, compressed air at two pressures was used for the purpose of creating a low pressure pneumatic conveying system. It is determined that when using these amplifications in the air boost, longer lengths of decay can be achieved in comparison to a no swirl system. This meant that the products transportation could be enhanced due to the addition of the swirl amplifiers. The experimental values were used to compare both designs. The more productive one was determined by its length of decay. As well as estimating the maximum obtainable distances for both swirl amplifiers at each particular amplification.

Determination of Latex Particle Size Distributions by Fractional Creaming with Sodium Alginate

1961 ◽  
Vol 34 (2) ◽  
pp. 433-445 ◽  
Author(s):  
E. Schmidt ◽  
P. H. Biddison
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Sodium Alginate ◽  
Mass Distribution ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Size Distributions ◽  
Particle Size Distributions

Abstract Knowledge of mass distribution of particle sizes in latex is very important to the latex technologist. Therefore, it is desirable to have available a simple method for the determination of mass distribution of particle sizes. This paper presents a method, based on fractional creaming of latex with sodium alginate, which can be used in any laboratory without special equipment. The method is particularly advantageous for analyzing latexes of very wide particle size distributions. When analyzed with an electron microscope, these latexes require counting a very large number of particles. McGavack found that partial creaming of normal hevea latex with ammonium alginate gives concentrates of larger average particle size than the original latex. He found that the average particle size in the cream approaches that of the original latex as the amount of creaming agent is increased. In a previous paper from this laboratory, Schmidt and Kelsey demonstrated that the phenomenon of fractionation according to particle size with increasing amounts of creaming agent is applicable in a wide variety of anionic latex systems and in colloidal silica. Their results indicated also the existence of a quantitative relationship, independent of the nature of the dispersed particles, between the concentration of creaming agent and size of creamed particles. Maron confirmed fractionation with respect to particle size as a consequence of partial creaming with alginate. He showed that the mass average particle sizes of fractions, determined optically, cumulate to that of the original latex. Although the previous paper by Schmidt and Kelsey implied the basic concept of a method of determining particle size distribution by fractional creaming, it was not exploited at that time. In order to adapt the fractional creaming phenomenon to a quantitative method for particle size determination, we required a more precise knowledge of the relation between creaming agent concentration and size of particles creamed. It was proposed to establish this relationship with the aid of the electron microscope. Various factors influencing the creaming of latex, such as polymer concentration, electrolyte, soap content, and variability of the creaming agent, had to be considered in standardizing the creaming procedure.

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