scholarly journals Considerations over the floating speed of a particle in vacuum pneumatic conveying sytems in flour milling

2016 ◽  
Vol 20 (1) ◽  
pp. 65-76
Author(s):  
Tanase Tanase
Keyword(s):  
Spherical Particle ◽  
Particle Diameter ◽  
Pipe Diameter ◽  
Pneumatic Conveying ◽  
Specific Mass ◽  
Magnus Force ◽  
Spherical Form ◽  
Flour Milling ◽  
Mass Load ◽  
The Given

Abstract The present paper is a theoretical study aiming for to assess the influence of the different factors such as deviation from the spherical form of a particle, specific mass load of the pneumatic conveying pipe and the report between the particle diameter and the pipe diameter, over the floating speed of a particle. For a non-spherical particle, the Magnus force is affecting the floating speed of the given particle by increasing or decreasing it. The equation deducted within the present study, describes the movement of a particle or a fluid swirl under the resultant force with emphasis on the evaluation of the nature and magnitude of the Magnus force. The same Magnus Force explains the movement of the swirls in fluids, as for the wind swirls (hurricane) or water swirls. The next part of the study relate the report between the particle diameter and the pipe diameter as well as the specific loads of the pipe, to the same floating speed. A differentiation in denominating the floating speed is proposed as well as that for the non-spherical particle the floating speed should be a domain, rather than a single value.

Application of the turbidity ratio method in the spherical particle size determination in the range m ∈ and α ∈

1979 ◽  
Vol 44 (7) ◽  
pp. 2064-2078 ◽  
Author(s):  
Blahoslav Sedláček ◽  
Břetislav Verner ◽  
Miroslav Bárta ◽  
Karel Zimmermann
Keyword(s):  
Refractive Index ◽  
Spherical Particle ◽  
Ratio Method ◽  
Refractive Indices ◽  
Relative Refractive Index ◽  
Particle Size Determination ◽  
The Individual ◽  
The Given ◽  
Turbidity Ratio ◽  
Selection Of

Basic scattering functions were used in a novel calculation of the turbidity ratios for particles having the relative refractive index m = 1.001, 1.005 (0.005) 1.315 and the size α = 0.05 (0.05) 6.00 (0.10) 15.00 (0.50) 70.00 (1.00) 100, where α = πL/λ, L is the diameter of the spherical particle, λ = Λ/μ1 is the wavelength of light in a medium with the refractive index μ1 and Λ is the wavelength of light in vacuo. The data are tabulated for the wavelength λ = 546.1/μw = 409.357 nm, where μw is the refractive index of water. A procedure has been suggested how to extend the applicability of Tables to various refractive indices of the medium and to various turbidity ratios τa/τb obtained with the individual pairs of wavelengths λa and λb. The selection of these pairs is bound to the sequence condition λa = λ0χa and λb = λ0χb, in which b-a = δ = 1, 2, 3; a = -2, -1, 0, 1, 2, ..., b = a + δ = -1, 0, 1, 2, ...; λ0 = λa=0 = 326.675 nm; χ = 546.1 : 435.8 = 1.2531 is the quotient of the given sequence.

Drag Force, Drag Torque, and Magnus Force Coefficients of Rotating Spherical Particle Moving in Fluid

2012 ◽  
Vol 30 (1) ◽  
pp. 55-67 ◽  
Author(s):  
N. Lukerchenko ◽  
Yu. Kvurt ◽  
I. Keita ◽  
Z. Chara ◽  
P. Vlasak
Keyword(s):  
Spherical Particle ◽  
Drag Force ◽  
Drag Torque ◽  
Magnus Force ◽  
Force Coefficients

Research on the Pneumatic Conveying of the Sand in the Horizontal Pipe Based on FLUENT

2016 ◽  
Vol 11 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Dan-yang Li ◽  
Shu Liu ◽  
Xiao-ning Wang
Keyword(s):  
Particle Diameter ◽  
Flow Characteristics ◽  
Axial Direction ◽  
Theoretical Research ◽  
Pneumatic Conveying ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Actual Measurement ◽  
Fluid Analysis ◽  
Euler Model

Abstract The pneumatic conveying experiment bed has been established to study the flow characteristics of air- solids two-phase flow in horizontal pipeline. Euler model was applied to simulate it based on analysis of Gambit and fluid analysis software-fluent. The simulated results indicated: under the same gas phase conveying flow and pressure, the bigger particle diameter is, the bigger pressure drop is in the horizontal pipeline. The smaller particle diameter is, the more uniform of the particle’s distribution is, and the more easily obtaining the acceleration is. Particle concentration at the bottom of the horizontal pipe is increasing in the axial direction, while close to the tail pipe it will be reduce. The simulated conclusion is consistent with the actual measurement results, herewith rendering some footing for engineering design and theoretical research on pneumatic conveying systems.

scholarly journals Numerical model of spherical particle saltation in a channel with a transversely tilted rough bed

2009 ◽  
Vol 57 (3) ◽  
pp. 182-190 ◽  
Author(s):  
Nikolay Lukerchenko ◽  
Siarhei Piatsevich ◽  
Zdenek Chara ◽  
Pavel Vlasak
Keyword(s):  
Numerical Model ◽  
Spherical Particle ◽  
Particle Trajectory ◽  
Particle Diameter ◽  
Shear Velocity ◽  
Rough Bed ◽  
Angle Of Deviation ◽  
Bed Slope ◽  
Straight Lines ◽  
Particle Saltation

Numerical model of spherical particle saltation in a channel with a transversely tilted rough bedThis paper deals with the numerical simulation of spherical particle saltation in a channel with a rough transversely tilted bed. The numerical model presented is based on the 3D model of spherical particle saltation developed by the authors, which takes into account the translational and rotational particle motion. The stochastic method and the concept of a contact zone were used for the calculation of a particle trajectory and its dependence on the bed lateral slope, particle diameter, and shear velocity. The effect of the bed lateral slope results in a deviation of the particle trajectory from the downstream direction. Some examples of the calculation are presented. The trajectories of the saltating particles starting their movements from one point were calculated and it was shown that they are of random character and together create a bundle or fascicle of trajectories. It was found that the centrelines of the bundles can be approximated by the straight lines for low and moderate values of the bed transverse slope, i.e. slopes less than 20°. The angle of deviation of the centreline from the downstream direction increases when the bed lateral slope and/or the particle diameters increase. However, with increasing shear velocity, the deviation angle decreases. Due to the lateral bed slope the particles are sorted according to their size, and the criteria for sorting particles were defined. An example of the particle sorting was calculated and the separable and non-separable regions were determined.

Three-dimensional numerical investigation of solid particle erosion in gate valves

2013 ◽  
Vol 228 (10) ◽  
pp. 1670-1679 ◽  
Author(s):  
Zhe Lin ◽  
Xiao-Dong Ruan ◽  
Zu-Chao Zhu ◽  
Xin Fu
Keyword(s):  
Three Dimensional ◽  
Particle Diameter ◽  
Flux Ratio ◽  
Pneumatic Conveying ◽  
Cavity Depth ◽  
Fluid Analysis ◽  
Orthogonal Experiments ◽  
Total Particle ◽  
Computational Fluid Dynamics Cfd ◽  
Pass Through

Gate valves, which are widely applied in pneumatic conveying systems, are vulnerable to erosion by particles. It is thus important to investigate the erosion in gate valves from the perspective of fluid analysis, and then to predict and improve their lifetimes. The effects of valve geometry and gas–solid flow conditions on valve erosion are investigated. Since a gate valve usually operates fully open to let fluid pass through, the geometry is simplified as a cavity. As gate valves are always placed horizontally in industrial situations, investigated cavities are placed horizontally, and the erosion damage to the bottom half of the aft wall (surface T), which is most likely to be eroded, is studied. A computational fluid dynamics (CFD) based two-way Eulerian–Lagrangian procedue is used to predict the erosion severity. The simulation procedure is validated by comparing the CFD results with those obtained from experiments of a pipe and an elbow, and also with the erosion region of a damaged valve. For convenience, the total erosion ratio, defined as the ratio of the mass eroded on a particular surface to the total particle mass passing through the pipe inlet during the same time, is introduced. The results show that the total erosion ratio of surface T is largely independent of the mass flux ratio, pipe diameter and cavity depth. Meanwhile, the total erosion ratio increases with cavity width and particle diameter, while it decreases with inlet velocity. According to the fitted results, a simple erosion formula is proposed and validated by the CFD results in another 16 orthogonal experiments. Furthermore, the formula is improved for various values of Brinell hardness of carbon steel and sharpness factors of particles.

203 Effect of Mean Particle Diameter on Pneumatic Conveying Characteristics of Suction Nozzle with Injection Pipe

2012 ◽  
Vol 2012.65 (0) ◽  
pp. 47-48
Author(s):  
Takaaki OSHIMA ◽  
Hiroshi KOUGUCHI ◽  
Minoru FUKUHARA ◽  
Hiroshi KATANODA ◽  
Hirokazu YAMAGUCHI
Keyword(s):  
Particle Diameter ◽  
Pneumatic Conveying ◽  
Suction Nozzle ◽  
Mean Particle Diameter

616 Effect of Particle Diameter on Pneumatic Conveying Characteristics of Suction Nozzle with Injection Pipe : 1st Report, In the case without Nozzle Depth

2014 ◽  
Vol 2014.67 (0) ◽  
pp. _616-1_-_616-2_
Author(s):  
Takahiro YANO ◽  
Hiroshi KOUGUCHI ◽  
Minoru FUKUHARA ◽  
Hiroshi KATANODA ◽  
Koki MORIYAMA
Keyword(s):  
Particle Diameter ◽  
Pneumatic Conveying ◽  
Suction Nozzle

Optical Measurement of the Relative Motion of a Spherical Particle in a Micro-Capillary

2011 ◽  
Author(s):  
Debjyoti Sen ◽  
David S. Nobes ◽  
Subir Bhattacharjee ◽  
Sushanta K. Mitra
Keyword(s):  
Velocity Field ◽  
Velocity Profile ◽  
Spherical Particle ◽  
Relative Motion ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Optical Measurement ◽  
Particle Diameter ◽  
Micro Channel ◽  
Neutrally Buoyant

The motion of a neutrally buoyant spherical micro particle suspended in a liquid inside a ‘U’ shaped micro channel is detected using particle tracking velocimetry. The ratio of the particle diameter to the hydraulic diameter of the channel is found to be 0.1. Poiseuille velocity profile is observed inside the micro channel and the spherical particle is convected with the Poiseuille velocity field. The magnitude of the lag factor is determined experimentally and is compared with the values reported in existing literature. The effect of other forces and interactions on the particle is quantitatively studied. It was found that effects of Brownian, Van der Waals and electrostatic forces do not significantly contribute to the velocity of the particle.

scholarly journals Determining the interfaces parameters for geotechnical modelling

2019 ◽  
Vol 97 ◽  
pp. 04042
Author(s):  
Armen Ter-Martirosyan ◽  
Vitalii Sidorov ◽  
Anastasia Almakaeva
Keyword(s):  
Numerical Simulation ◽  
Laboratory Tests ◽  
Underground Structure ◽  
Particle Diameter ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Internal Forces ◽  
Standard Values ◽  
The Given

The article discusses the interaction of concrete structures with the soil, made on the basis of laboratory tests and numerical simulation. The objectives of the study were to obtain the strength characteristics at the contact of two different materials, to compare the obtained value of the strength reduction factor with the standard values, and also to determine the extent to which the interface must be taken into account when conducting numerical geotechnical calculations. The study was carried out using a direct shear test device, where the strength reduction factor was obtained, which characterizes the conditions of interaction between different materials at their contact. According to the results of numerical simulation, one can see how the consideration of the given characteristics of the material of the contact element affects the internal forces arising in the underground structure and its displacements. The test results showed that the particle diameter has a different effect on shear strength at the same level of normal stress. On the basis of the results obtained, conclusions were drawn on what needs to be paid more attention to when conducting laboratory tests, how strongly the consideration of contact elements with the correct set of properties affects the internal forces of the underground structure. Also, the remaining problems and factors not considered in this study determined the prospects for further research on the topic under consideration.

Impact of particle diameter, density and sphericity on minimum pickup velocity of binary mixtures in gas-solid pneumatic conveying

2016 ◽  
Vol 297 ◽  
pp. 311-319 ◽  
Author(s):  
Aditya Anantharaman ◽  
Andy Cahyadi ◽  
Kunn Hadinoto ◽  
Jia Wei Chew
Keyword(s):  
Binary Mixtures ◽  
Particle Diameter ◽  
Pneumatic Conveying
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