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.

scholarly journals Experimental investigation of coarse particles-water mixture flow in horizontal and inclined pipes

2014 ◽  
Vol 62 (3) ◽  
pp. 241-247 ◽  
Author(s):  
Pavel Vlasák ◽  
Zdeněk Chára ◽  
Jan Krupička ◽  
Jiří Konfršt
Keyword(s):  
Dominant Mode ◽  
Solid Particles ◽  
Coarse Grained ◽  
Water Mixture ◽  
Mixture Flow ◽  
Horizontal Pipe ◽  
Pressure Drops ◽  
Steel Pipes ◽  
Inner Diameter ◽  
Inclined Pipes

Abstract The effect of solid concentration and mixture velocity on the flow behaviour, pressure drops, and concentration distribution of coarse particle-water mixtures in horizontal, vertical, and inclined smooth stainless steel pipes of inner diameter D = 100 mm was experimentally investigated. Graded basalt pebbles were used as solid particles. The study revealed that the coarse-grained particle-water mixtures in the horizontal and inclined pipes were significantly stratified. The solid particles moved principally in a layer close to the pipe invert; however for higher and moderate flow velocities, particle saltation became the dominant mode of particle conveyance. Frictional pressure drops in the horizontal pipe were found to be markedly higher than in the vertical pipe, while the frictional pressure drops in the ascending pipe increased with inclination angle up to about 30°.

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 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 Catalytic Activity of Ni3Al Foils in Methanol Reforming

2010 ◽  
Vol 636-637 ◽  
pp. 895-900 ◽  
Author(s):  
P. Jozwik ◽  
R. Grabowski ◽  
Z. Bojar
Keyword(s):  
Catalytic Activity ◽  
Chemical Properties ◽  
Methanol Conversion ◽  
Advanced Materials ◽  
Coarse Grained ◽  
High Tech ◽  
High Catalytic Activity ◽  
Water Mixture ◽  
Catalytic Coating ◽  
Thin Foils

Intermetallic Ni3Al–based alloys (doped with zirconium and boron) represent a group of advanced materials with potential outstanding physical and chemical properties (such as high catalytic activity and structural stability in corrosive environments) that make them a considerable candidate for many high-tech applications. In this paper, the catalytic activity of fully dense Ni3Al-based thin foils (as thin as 50 m) possessing structures with micrometer or nanometer grain sizes is discussed. The examined material, without any additional catalytic coating, was successfully produced from as-cast coarse-grained sheets by heavy cold rolling and recrystallisation with an appropriately chosen set of parameters. The examination focuses on methanol and methanol/water mixture decomposition into H2 and CO at temperatures up to 530OC in a quartz reactor. Except for these products, a small amount (below 1%) of CO2 and dimethyl ether was observed. The catalyzed reaction began effectively at about 400OC, with a methanol conversion of about 90% or higher.

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.

Uncertainty Analysis for the Measurement of Oil-Water Flow Parameters, Part II: Pressure Drop

2020 ◽  
Vol 15 (1) ◽  
pp. 1-7
Author(s):  
A. Abubakar
Keyword(s):  
Pressure Drop ◽  
Water Flow ◽  
Flow Rate ◽  
Tap Water ◽  
Standard Uncertainty ◽  
Water Volume ◽  
Water Mixture ◽  
Oil Water ◽  
Pressure Transmitter ◽  
Inclined Pipes

The need to ensure qualitative and reliable measurement of pressure drop of the oil-water flow cannot be over emphasized. In this regard, this study focused on the investigation of uncertainty in the measurement of pressure drop of oil-water flow in different acrylic pipe inclinations (0, +5ᴼ, +10ᴼ and -5ᴼ) and diameters (30.6-, 55.7- and 74.7-mm ID). The working fluids were tap water and mineral-based hydraulic oil (Shell Tellus S2 V 15), with medium viscosity and density of 24 cP and 872 kgm-3 respectively while the interfacial tension between the water and the oil was 12.9 mN/m at 25 ᴼC. The selected flow conditions were 0.5 and 1.0 m/s mixture velocities each at 0.1, 0.5 and 0.9 input water volume fractions. The repeatability, accuracy of the pressure transmitter, flow rate of the oil-water mixture and holdup (particularly for the inclined flow) were the sources of errors in the measurement of the pressure drop. The results showed that the average relative uncertainties in the pressure drop in 30.6-mm ID pipe were ±4.6 %, ±10.8 %, ±11.2 % and ±10.8 % in the 0ᴼ, +5ᴼ, +10ᴼ and -5ᴼ inclined flows respectively. Similarly, the average relative uncertainties in the pressure drop in the horizontal 55.7-mm and 74.7-mm ID pipes were ±5.7 % and ±7.5 % respectively. The largest contribution to the uncertainty in the pressure drop came from the flow rate and water holdup in the horizontal and inclined pipes respectively. The least contribution in both  horizontal and inclined pipes came from the accuracy of the pressure transmitter. Key words: Oil-water flow; Pressure drops; Standard uncertainty, Combined standard uncertainty; Expanded uncertainty

scholarly journals Anticardiolipin antibodies recognize beta 2-glycoprotein I structure altered by interacting with an oxygen modified solid phase surface.

1994 ◽  
Vol 179 (2) ◽  
pp. 457-462 ◽  
Author(s):  
E Matsuura ◽  
Y Igarashi ◽  
T Yasuda ◽  
D A Triplett ◽  
T Koike
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gamma Ray ◽  
Solid Phase ◽  
Anticardiolipin Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Polystyrene Surface ◽  
Glycoprotein I ◽  
Latex Beads ◽  
Beta 2 ◽  
Phase Surface

Anticardiolipin antibodies (aCL) derived from the sera of individuals exhibiting the antiphospholipid syndrome (APS) directly bind to beta 2-glycoprotein I (beta 2-GPI), which is adsorbed to an oxidized polystyrene surface. Oxygen atoms were introduced on a polystyrene surface by irradiation with electron or gamma-ray radiation. X-ray photoelectron spectroscopy revealed the irradiated surfaces were oxidized to generate C-O and C = O moieties. aCL derived from either APS patients or (NZW x BXSB)F1 mice bound to beta 2-GPI coated on the irradiated plates, depending on the radiation dose. Antibody binding to beta 2-GPI on the irradiated plates was competitively inhibited by simultaneous addition of cardiolipin (CL)-coated latex beads mixed together with beta 2-GPI but were unaffected by addition of excess beta 2-GPI, CL micelles, or CL-coated latex beads alone. There was a high correlation between binding values of aCL in sera from 40 APS patients obtained by the anti-beta 2-GPI enzyme-linked immunosorbent assay (ELISA) using the irradiated plates and those by the beta 2-GPI-dependent aCL ELISA. Therefore, aCL have specificity for an epitope on beta 2-GPI. This epitope is expressed by a conformational change occurring when beta 2-GPI interacts with an oxygen-substituted solid phase surface.

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