scholarly journals Experimental investigation of fine-grained settling slurry flow behaviour in inclined pipe sections

2019 ◽  
Vol 67 (2) ◽  
pp. 113-120
Author(s):  
Pavel Vlasák ◽  
Zdeněk Chára ◽  
Václav Matoušek ◽  
Jiří Konfršt ◽  
Mikoláš Kesely
Keyword(s):  
Concentration Distribution ◽  
Flow Behaviour ◽  
Narrow Particle Size Distribution ◽  
Local Concentration ◽  
Slurry Flow ◽  
Pressure Drops ◽  
Fine Grained ◽  
Limit Velocity ◽  
The Difference ◽  
Inclined Pipe

Abstract For the safe and economical design and operation of freight pipelines it is necessary to know slurry flow behaviour in inclined pipe sections, which often form significant part of pipelines transporting solids. Fine-grained settling slurry was investigated on an experimental pipe loop of inner diameter D = 100 mm with the horizontal and inclined pipe sections for pipe slopes ranging from −45° to +45°. The slurry consisted of water and glass beads with a narrow particle size distribution and mean diameter d50 = 180 µm. The effect of pipe inclination, mean transport volumetric concentration, and slurry velocity on flow behaviour, pressure drops, deposition limit velocity, and concentration distribution was studied. The study revealed a stratified flow pattern of the studied slurry in inclined pipe sections. Frictional pressure drops in the ascending pipe were higher than that in the descending pipe, the difference decreased with increasing velocity and inclination. For inclination less than about 25° the effect of pipe inclinations on deposition limit velocity and local concentration distribution was not significant. For descending pipe section with inclinations over −25° no bed deposit was observed.

scholarly journals Effect of pipe inclination on flow behaviour of fine-grained settling slurry

2019 ◽  
Vol 213 ◽  
pp. 02094
Author(s):  
Pavel Vlasak ◽  
Zdenek Chara ◽  
Vaclav Matousek ◽  
Jiri Konfrst ◽  
Mikolas Kesely
Keyword(s):  
Concentration Distribution ◽  
Gamma Ray ◽  
Deposition Velocity ◽  
Narrow Particle Size Distribution ◽  
Local Concentration ◽  
Horizontal Pipe ◽  
Pressure Drops ◽  
Fine Grained ◽  
Inclined Pipe ◽  
Pipe Inclination

The effect of flow parameters of fine-grained settling slurry on the pressure drop-velocity relationship, deposition limit velocity and local concentration distribution was studied in an experimental pipe loop of inner diameter D = 100 mm with inclinable pipe sections for pipe inclination ranging from – 45° to +45°. The slurry consisted from water and narrow particle size distribution glass beads of mean diameter d50 = 0.18 mm. The concentration distribution was studied with application of a gamma-ray densitometry. The deposition velocity was defined as the flow velocity at which stationary deposit started to be formed at the pipe invert. The study revealed the stratified flow pattern of the studied slurry in inclined pipe sections, for slurry velocities below to the deposition limit sliding or stationary bed were created in ascending pipe sections. For low pipe inclination (α < ± 25°) the effect of inclination on local concentration distribution was not significant. Mean transport concentration for descending flow was lower than that for the ascending flow Deposition limit in inclined pipe was slightly lower than that in horizontal pipe. Frictional pressure drops in ascending pipe were higher than that in descending pipe, the difference decreased with increasing velocity and inclination.

scholarly journals Flow behaviour and local concentration of coarse particles-water mixture in inclined pipes

2017 ◽  
Vol 65 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Pavel Vlasak ◽  
Zdenek Chara ◽  
Jiri Konfrst
Keyword(s):  
Particle Size ◽  
Gamma Ray ◽  
Dominant Mode ◽  
Solid Particles ◽  
Flow Behaviour ◽  
Coarse Particle ◽  
Narrow Particle Size Distribution ◽  
Local Concentration ◽  
Water Mixture ◽  
Mixture Flow

AbstractNarrow particle size distribution basalt pebbles of mean particle size 11.5 mm conveyed by water in the pipe sections of different inclination were investigated on an experimental pipe loop, consisting of smooth stainless steel pipes of inner diameterD= 100 mm. Mixture flow-behaviour and particles motion along the pipe invert were studied in a pipe viewing section, the concentration distribution in pipe cross-section was studied with the application of a gamma-ray densitometer. The study refers to the effect of mixture velocity, overall concentration, and angle of pipe inclination on chord-averaged concentration profiles and local concentration maps, and flow behaviour of the coarse particle-water mixtures. The study revealed that the coarse particle-water mixtures in the inclined pipe sections were significantly stratified, the solid particles moved principally close to the pipe invert, and for higher and moderate flow velocities particle saltation becomes the dominant mode of particle conveying.

scholarly journals Concentration distribution and deposition limit of medium-coarse sand-water slurry in inclined pipe

2020 ◽  
Vol 68 (1) ◽  
pp. 83-91
Author(s):  
Pavel Vlasák ◽  
Václav Matoušek ◽  
Zdeněk Chára ◽  
Jan Krupička ◽  
Jiří Konfršt ◽  
...  
Keyword(s):  
Inclination Angle ◽  
Concentration Distribution ◽  
Silica Sand ◽  
Narrow Particle Size Distribution ◽  
Mean Velocity ◽  
Horizontal Pipe ◽  
Slurry Concentration ◽  
Limit Velocity ◽  
Water Slurry ◽  
Pipe Inclination

AbstractSand-water slurry was investigated on an experimental pipe loop of inner diameter D = 100 mm with the horizontal, inclined, and vertical smooth pipe sections. A narrow particle size distribution silica sand of mean diameter 0.87 mm was used. The experimental investigation focused on the effects of pipe inclination, overall slurry concentration, and mean velocity on concentration distribution and deposition limit velocity. The measured concentration profiles showed different degrees of stratification for the positive and negative pipe inclinations. The degree of stratification depended on the pipe inclination and on overall slurry concentration and velocity. The ascending flow was less stratified than the corresponding descending flow, the difference increasing from horizontal flow up to an inclination angle of about +30°. The deposition limit velocity was sensitive to the pipe inclination, reaching higher values in the ascending than in the horizontal pipe. The maximum deposition limit value was reached for an inclination angle of about +25°, and the limit remained practically constant in value, about 1.25 times higher than that in the horizontal pipe. Conversely, in the descending pipe, the deposition limit decreased significantly with the negative slopes and tended to be zero for an inclination angle of about −30°, where no stationary bed was observed.

EFFECT OF PIPE INCLINATION ON COARSE-GRAINED PARTICLE-WATER MIXTURES FLOW

2020 ◽  
Vol 23 (2) ◽  
Author(s):  
Pavel Vlasak ◽  
◽  
Zdenek Chara ◽  
Jiri Konfrst ◽  
Jan Krupicka ◽  
...  
Keyword(s):  
Concentration Distribution ◽  
Gamma Ray ◽  
Solid Phase ◽  
Dominant Mode ◽  
Coarse Grained ◽  
Local Concentration ◽  
Water Mixture ◽  
Pressure Drops ◽  
Inclined Pipes ◽  
Pipe Inclination

The effect of the mixture velocity, solid concentration, and pipe inclination on the coarse-grained particle–water mixtures flow behaviour, concentration distribution, and pressure drops were experimentally studied in horizontal, vertical, and inclined pipes of inner diameter D=100 mm. Graded basalt gravel was used as a solid phase. The local concentration distribution was studied with the application of a gamma-ray densitometer. The study revealed the stratified flow pattern of the coarse particle-water mixture in horizontal and inclined pipes. The particles moved principally close to the pipe invert, and particle saltation becomes the dominant mode of particle conveying for higher and moderate flow velocities. The frictional pressure droops in ascending pipe increases with increasing pipe inclination up to about 30 degrees, then gradually decreases. For the pipe inclination lower than about 30°, the effect of pipe inclination on local concentration distribution was not significant. The in-situ concentration reached higher values in the ascending than in the descending sections.

FG-LiquID

2021 ◽  
Vol 5 (3) ◽  
pp. 1-27
Author(s):  
Yumeng Liang ◽  
Anfu Zhou ◽  
Huanhuan Zhang ◽  
Xinzhe Wen ◽  
Huadong Ma
Keyword(s):  
Alcohol Concentration ◽  
Coarse Grained ◽  
Robust Identification ◽  
Fine Grained ◽  
Fresh Milk ◽  
Average Accuracy ◽  
Coarse Grained Material ◽  
Potential Applications ◽  
Fine Grained Material ◽  
The Difference

Contact-less liquid identification via wireless sensing has diverse potential applications in our daily life, such as identifying alcohol content in liquids, distinguishing spoiled and fresh milk, and even detecting water contamination. Recent works have verified the feasibility of utilizing mmWave radar to perform coarse-grained material identification, e.g., discriminating liquid and carpet. However, they do not fully exploit the sensing limits of mmWave in terms of fine-grained material classification. In this paper, we propose FG-LiquID, an accurate and robust system for fine-grained liquid identification. To achieve the desired fine granularity, FG-LiquID first focuses on the small but informative region of the mmWave spectrum, so as to extract the most discriminative features of liquids. Then we design a novel neural network, which uncovers and leverages the hidden signal patterns across multiple antennas on mmWave sensors. In this way, FG-LiquID learns to calibrate signals and finally eliminate the adverse effect of location interference caused by minor displacement/rotation of the liquid container, which ensures robust identification towards daily usage scenarios. Extensive experimental results using a custom-build prototype demonstrate that FG-LiquID can accurately distinguish 30 different liquids with an average accuracy of 97%, under 5 different scenarios. More importantly, it can discriminate quite similar liquids, such as liquors with the difference of only 1% alcohol concentration by volume.

scholarly journals A new type of slumping-induced soft-sediment deformation structure: the envelope structure

Geologos ◽  
2019 ◽  
Vol 25 (2) ◽  
pp. 111-124
Author(s):  
Uk Hwan Byun ◽  
A.J. Tom van Loon ◽  
Yi Kyun Kwon ◽  
Kyoungtae Ko
Keyword(s):  
Slope Failure ◽  
Gravity Flow ◽  
Soft Sediment ◽  
Deformation Structure ◽  
Rare Type ◽  
Fine Grained ◽  
Sediment Deformation ◽  
Soft Sediment Deformation ◽  
The Difference ◽  
Siliciclastic Rocks

Abstract The sediments of the Cretaceous Gyeokpori Formation in south-western South Korea accumulated in a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity resulted in unstable lake margins inducing a dominance of gravity-flow deposits. The high sedimentation rate facilitated soft-sediment deformation on the sloping margin. The deposition of numerous gravity-flow deposits resulted in a vertically heterolithic stratification. The slumps are composed of different lithologies, which is expressed in different types of deformation due to the difference in cohesion between sandy and mussy layers within the slumps. Coarser-grained (cohesionless) slumps tend to show more chaotic deformation of their lamination or layering. The difference in slumping behaviour of the cohesive and non-cohesive examples is explained and modelled. A unique soft-sediment deformation structure is recognized. This structure has not been described before, and we call it ‘envelope structure’. It consists of a conglomerate mass that has become entirely embedded in fine-grained sediment because slope failure took place and the fine-grained material slumped down with the conglomerate ‘at its back’. The cohesive laminated mudstone formed locally slump folds that embedded the non-cohesive overlying conglomerate unit, possibly partly due to the bulldozing effect of the latter. This structure presumably can develop when the density contrast with the underlying and overlying deposits is exceptionally high. The envelope structure should be regarded as a special – and rare – type of a slumping-induced deformation structure.

A Tool for Discourse Analysis and Visualization

2013 ◽  
Vol 5 (2) ◽  
pp. 55-71 ◽  
Author(s):  
Costin-Gabriel Chiru ◽  
Stefan Trausan-Matu
Keyword(s):  
Discourse Analysis ◽  
Intrinsic Structure ◽  
Fine Grained ◽  
Construction Of Knowledge ◽  
Cultural Paradigms ◽  
Starting Point ◽  
Social Construction Of Knowledge ◽  
Before And After ◽  
The Difference ◽  
Polyphonic Model

In this paper the authors present a system that combines the cognitive and socio-cultural paradigms in the field of discourse analysis in order to analyze both texts written by only one author (for example narrations) and those written collaboratively (chat conversations, blogs, wikis, forums). The novelty of their approach is that the majority of the existing applications are oriented on analyzing only one of these two types, an adaptation being necessary for the analysis of the other type. Another advantage of the presented system is that since it is centered on a dialogistic polyphonic model considering topics as inter-animated voices, it could show the difference between coarse- and fine-grained coherence in discourse, therefore allowing the analysis of a text from two different viewpoints: a) its intrinsic structure and cohesion and b) how well this text fits in a stream of texts (whether it is or not cohesive with the texts before and after it). The dialogistic polyphonic model was used as a starting point for a method for analyzing collaboration and social construction of knowledge in groups and communities using textual interactions, and for several implemented systems for providing computerized support to the analysis method through visualizations and feedback generation.

Computational Investigation on the Dispersive Transport of Angiographic Contrast Injected Antegradely Into Flow in a Tube

2007 ◽  
Author(s):  
Qing Hao ◽  
Baruch B. Lieber
Keyword(s):  
Coordinate System ◽  
Cross Section ◽  
Single Molecule ◽  
Molecular Diffusion ◽  
Local Concentration ◽  
Dispersive Transport ◽  
Cross Sectional ◽  
Advection Dispersion ◽  
The Cross ◽  
The Difference

When a solute such as angiographic contrast is introduced into a solvent such as blood analog fluid flowing in a straight circular tube, it spreads under the combined action of molecule diffusion and the variation of velocity over the cross-section [8]. If two molecules are being carried in the flow, for example, one in the center and one near the wall, the rate of separation caused by the difference in bulk velocity will greatly exceed that caused by molecule motion. Given enough time, any single molecule would wander randomly throughout the cross section of the pipe because of molecular diffusion, and would sample at random all the advective velocities [4]. Therefore, Taylor [8] adopted the Lagrangian approach to the problem, casting the equations in a coordinate system that moves with the average velocity of the flow and replacing the molecular diffusion coefficient with a dispersion coefficient, and the local concentration with the cross sectional mean concentration. Recasting Taylor’s equation in an inertial coordinate system one obtained the so called advection-dispersion equation.

Effect of Pipe Inclination on Settling Slurry Flow Near Deposition Velocity

2018 ◽  
Author(s):  
Václav Matoušek ◽  
Mikoláš Kesely ◽  
Jiři Konfršt ◽  
Pavel Vlasák
Keyword(s):  
Deposition Velocity ◽  
Experimental Results ◽  
Engineering Practice ◽  
Local Concentration ◽  
Slurry Flow ◽  
Layered Model ◽  
Frictional Pressure Drop ◽  
Model Predictions ◽  
Slurry Flows ◽  
Pipe Inclination

Inclined slurry flows occur often in industrial applications such as mining and dredging. Pipelines transporting slurries contain inclined sections of various lengths and slopes. If the transported slurry is settling slurry then pipe inclination considerably affects flow structure and behavior. We discuss settling slurry flow near and at the deposition limit at which stationary deposit starts to be formed at the bottom of the pipe. In particular, we focus on the effect of the pipe slope on the deposition velocity, and on the solids distribution and manometric hydraulic gradient in flow round the deposition limit. We introduce our new layered model for inclined settling slurry flows and demonstrate its predictive capabilities. Model predictions are verified by our experiment in a laboratory loop. We also introduce our new experimental approach to a detection of the deposition velocity based on radiometric sensing of the change of local concentration of solids at the bottom of a pipe. Our experiments cover a broad range of flow slopes and contain measurements of solids distribution in a pipe cross section. Experimental results show that the degree of flow stratification and frictional pressure drop decrease with the increasing angle of inclination in the ascending pipe while the opposite applies in the descending pipe, which affects the deposition velocity and other related flow parameters. A comparison with model predictions demonstrates that experimentally observed effects of pipe inclination are reproduced well by the layered model. Predicted deposition velocities, pressure drops and solids distributions are in a good agreement with the experimental results and indicate suitability of the model for engineering practice.

scholarly journals Granite micro-porosity changes due to fracturing and alteration: secondary mineral phases as proxies for porosity and permeability estimation

2018 ◽  
Author(s):  
Martin Staněk ◽  
Yves Géraud
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Fluorescent Light ◽  
Fracture Density ◽  
Void Space ◽  
Mercury Intrusion ◽  
Fine Grained ◽  
Mineral Phases ◽  
Space Geometry ◽  
Porosity And Permeability ◽  
The Difference

Abstract. Several alteration facies of fractured Lipnice granite are studied in detail on borehole samples by means of mercury intrusion porosimetry, polarized and fluorescent light microscopy and microprobe chemical analyses. The goal is to describe the granite void space geometry in vicinity of fractures with alteration halos and to link specific geometries with simply detectable parameters to facilitate quick estimation of porosity and permeability based on e.g. drill cuttings. The core of the study are results of porosity and throat size distribution analyses on 21 specimens representing unique combinations of fracture-related structures within 6 different alteration facies basically differing in secondary phyllosilicate chemistry and porosity structure. Based on a simple model to calculate permeability from the measured porosities and throat size distributions the difference in permeability between the fresh granite and the most fractured and altered granite is 5 orders of magnitude. Our observations suggest that the porosity, the size of connections and the proportion of crack porosity increase with fracture density, while precipitation of iron-rich infills as well as of fine grained secondary phyllosilicates acts in the opposite way. Different styles and intensities of such end-member agents shape the final void space geometry and imply various combinations of storage, transport and retardation capacity for specific structures. The study also shows the possibility to use the standard mercury intrusion porosimetry with advanced experimental setting and data treatment to distinguish important differences in void space geometry within a span of few per cent of porosity.

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