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°.

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 Flow Structure of Coarse-Grained Slurry in A Horizontal Pipe

2012 ◽  
Vol 60 (2) ◽  
pp. 115-124 ◽  
Author(s):  
Pavel Vlasak ◽  
Bohus Kysela ◽  
Zdenek Chara
Keyword(s):  
Flow Structure ◽  
Flow Behaviour ◽  
Coarse Grained ◽  
Flow Visualisation ◽  
Turbulent Regime ◽  
Horizontal Pipe ◽  
Steel Pipes ◽  
Carrier Liquid ◽  
Inner Diameter ◽  
Particle Saltation

Flow Structure of Coarse-Grained Slurry in A Horizontal Pipe The flow behaviour of coarse-grained slurry depends on particle size, shape, density and concentration, and on the density and rheological properties of the carrier liquid. The present paper describes the results of an experimental investigation and flow visualisation of model coarse-grained particle-water mixtures in a closed pipe loop with smooth stainless steel pipes of inner diameter 36 mm. Glass balls and washed graded pebble gravel of mean diameter d50= 6 mm were used as model coarse-grained material. The effect of slurry velocity and particle concentration on the slurry flow behaviour and pressure drop in the turbulent regime was evaluated. Particle distribution in the pipe cross-section and motion of particles along the pipe invert, particle saltation and particle conveying in the carrier liquid were investigated in a transparent pipe viewing section and motion of individual particles was described. Velocity profiles of the carrier liquid and conveyed particles were determined.

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 Analysis on a Snow-Water Mixture Flow in a Horizontal Pipe by Three-Layer Model

1989 ◽  
Vol 5 (4) ◽  
pp. 3-15
Author(s):  
HIROSHI TAKAHASHI ◽  
MIKIO SASAKI ◽  
TOSHIO KAWASHIMA
Keyword(s):  
Water Mixture ◽  
Layer Model ◽  
Mixture Flow ◽  
Horizontal Pipe ◽  
Snow Water

Energy Loss in Snow-Water Mixture Flow

2003 ◽  
Author(s):  
Mikio Sasaki ◽  
Takahiro Takeuchi ◽  
Hiroshi Takahashi
Keyword(s):  
Specific Gravity ◽  
Energy Loss ◽  
Friction Factor ◽  
Pure Water ◽  
Solid Particles ◽  
Water Mixture ◽  
Solid Concentration ◽  
Mixture Flow ◽  
Snow Water ◽  
Relative Friction

Energy losses in the solid-water mixture flow where the density of solid is nearly equal to that of fluid were observed in horizontal pipelines. The observation was carried out to investigate the influence that the specific gravity of the solid particles exerted on the energy loss. A relative friction factor based on the friction factor of the pure water flow becomes larger as the solid concentration increases in the mixture flow of solid particles with the specific gravity 0.86 and 1.04. The relative friction factor is given with the Froude number, the solid concentration and the specific gravity of solid.

CFD Simulations of Oil-Water Flow Behavior in Horizontal Pipe Separator

2019 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Flow Behavior ◽  
Scale Up ◽  
Water Mixture ◽  
Hexahedral Mesh ◽  
Cfd Simulations ◽  
Mixture Flow ◽  
Horizontal Pipe ◽  
Vof Model ◽  
Oil Water ◽  
Grid Convergence Index

Abstract Horizontal Pipe Separators (HPS©) are used for separation of oil and water especially in subsea environment owing to its simplicity, installation, and operation. In the present work, the flow phenomena in the HPS with 0.0762m ID and 10.3 m long separating oil and water with specific gravities of 1 and 0.857 is simulated and analyzed using ANSYS Fluent 16. Hexahedral mesh with boundary layers has been done utilizing ANSYS design modeler for this analysis. A grid independence study is performed on 3 different mesh grids using grid convergence index. 3-D simulations are carried out using a Hybrid Eulerian-Eulerian Multifluid VOF model for watercuts ranging from 20 to 80% and a mixture velocity of 0.08 m/s. The CFD simulations analyzed the effect of watercut on the oil-water mixture flow behavior and the entry region required for the oil and water to separate in the HPS. These simulation results are validated against acquired experimental data by Othman in 2010. These simulations provide an insight to understand the effects of diameter, watercut, and mixture velocities on the performance of HPS to aid in its design and scale up/down studies.

Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits

2014 ◽  
Vol 70 (5) ◽  
pp. 871-877 ◽  
Author(s):  
Fahri Ozkan ◽  
M. Cihat Tuna ◽  
Ahmet Baylar ◽  
Mualla Ozturk
Keyword(s):  
Froude Number ◽  
High Speed ◽  
Water Mixture ◽  
High Speed Flow ◽  
Mixture Flow ◽  
Speed Flow ◽  
Aeration Efficiency ◽  
High Head ◽  
Closed Conduit ◽  
Air Vent

Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

Technical regulation for the values of hydraulic parameters of used metal pipes in order to extend the period of their use

2021 ◽  
Vol 18 (3) ◽  
pp. 421-427
Author(s):  
Oleg A. PRODOUS ◽  
◽  
Lev D. TEREKHOV ◽  
Petr P. YAKUBCHIK ◽  
Alexander S. CHERNIKH ◽  
...  
Keyword(s):  
Practical Importance ◽  
Hydraulic Calculation ◽  
Technical Regulation ◽  
Supply Networks ◽  
Steel Pipes ◽  
Head Losses ◽  
Metal Pipes ◽  
Inner Diameter ◽  
Pumping Equipment ◽  
The Given

Objective: To compare the characteristics of hydraulic potential in worn steel pipes with internal deposits subjected to cleaning by mechanical and chemical methods. Methods: Calculated dependencies are used for hydraulic calculation of new metal pipes and pipes with internal deposits. Results: A calculated dependence was obtained to determine the value of the inner diameter of pipes with any thickness of the layer of internal deposits. The concept of an efficient pipeline is introduced and a comparison made of the values of head losses in new pipes and in pipes with internal deposits. A specific practical example is considered. For the given example, compare the values of energy consumption of pumping equipment for two methods of cleaning the inner surface of pipes. Measures are indicated to ensure the efficiency of operation of water supply networks. Practical importance: It is shown that the chemical method of technical regulation of the hydraulic characteristics of new steel pipes provides an extension of the period of their further use.

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.

scholarly journals Research of friction characteristics on the hydraulic transportation in inclined slurry-pipe

2020 ◽  
Vol 198 ◽  
pp. 01030
Author(s):  
Wang Tieli
Keyword(s):  
Experimental Data ◽  
Momentum Transfer ◽  
Interaction Mechanism ◽  
Hydraulic Gradient ◽  
Solid Particles ◽  
Friction Loss ◽  
Acceleration Time ◽  
New Model ◽  
Inclined Pipe ◽  
Inclined Pipes

By analyzing the momentum transfer and velocity both of solid particles and water over the acceleration time of solid particles, as well as interaction mechanism between water and solid particals, a new model is proposed to predict friction loss for setting slurry flow in inclined pipe. The hydraulic gradient formula for inclined pipes summarized by the author is confirmed by a large amount of experimental data. The results show that the deviation between the theoretical value of the model proposed by the author and the measured value is not more than 13.33%, which is the smallest among all reports.

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