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 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°.

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.

Simulation of Intermittent Flow Development in a Horizontal Pipe

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Hamed Nasrfard ◽  
Hassan Rahimzadeh ◽  
Ali Ahmadpour ◽  
Ehsan Amani
Keyword(s):  
Three Dimensional ◽  
Intermittent Flow ◽  
Horizontal Pipe ◽  
Vof Model ◽  
New Findings ◽  
Air Water Interface ◽  
Elongated Bubble ◽  
Bubble Length ◽  
Computational Fluid Dynamics Cfd ◽  
Inner Diameter

In this study, detailed three-dimensional (3D) numerical simulations of intermittent multiphase flows were carried out to investigate the slug initiation process and various features of intermittent flows inside a horizontal pipe. Air and water are used as working fluids. The domain used for simulations is a 14.4 m long pipe with 54 mm inner diameter. The volume of fluid (VOF) model was used to capture the air/water interface and its temporal evolution. Using the developed computational fluid dynamics (CFD) model, the slug formation and propagation along horizontal circular pipe were successfully predicted and studied comprehensively. Slug length and the frequency of slug formation, as two main features of intermittent flow, were used to validate the model against experimental results and available correlations in the literature. Three-dimensional numerical simulation of intermittent flow proved to be a powerful tool in tackling limitations of experiments and providing detailed data about various features of the intermittent flow. The effect of gas and liquid superficial velocities on the liquid slug and elongated bubble length was explored. Moreover, the study revealed new findings related to the elongated bubble shape and velocity field in the slug unit.

The Study of Counting the Strapping Steel Pipes Based on Image Recognition

2012 ◽  
Vol 490-495 ◽  
pp. 3831-3835
Author(s):  
Xue Hua Li ◽  
Hui Min Liang ◽  
Zhi Kai Cao ◽  
Zhong Yun Jiang ◽  
Long Chen
Keyword(s):  
Mathematical Morphology ◽  
Image Recognition ◽  
Small Area ◽  
Detection Rate ◽  
Hough Transformation ◽  
Steel Pipes ◽  
Economic Profit ◽  
Invariant Moments ◽  
Good Market ◽  
Inner Diameter

The accurate count has been realized and the expected results have been acquired by the image of the end of steel pipes recognized, which has a good market prospect and economic profit. The mathematical morphology was used to preprocess image and inspect the edge of the target. An improved Hough Transformation was applied to recognize inner diameter of steel pipes, which improved the detection rate. The Hu invariant moments described in the area was used to recognize inner diameter of steel pipes, which realized the pipe sum accurately. The method to count points was used to realize the sum of pipes according to the condition that the inner diameter circus of binary pipe image was corroded more times came to change into small area.

scholarly journals Calculation of Hydraulic Resistance in the Case of a Diffuser and a Confuser in a Horizontal Pipe

2021 ◽  
Vol 137 (6) ◽  
pp. 62-64
Author(s):  
A. M. Khurmamatov ◽  
◽  
G. B. Rakhimov ◽  
Keyword(s):  
Hydraulic Resistance ◽  
Pressure Loss ◽  
Head Loss ◽  
Sudden Expansion ◽  
Horizontal Pipe ◽  
Rate Of Increase ◽  
Inner Diameter

The main results of the calculation of the head loss with a smooth expansion and narrowing of the horizontal pipe, which has the following geometric dimensions; - the inner diameter of the pipe with a narrowing of 25 mm and an expansion of 50 mm. The pressure loss of the smooth expansion of the pipe at an oil velocity of 0.2–1.0 m/s has a smooth rate of increase from 0.002 to 0.032 m. With a smooth narrowing of the pipe, the head loss is from 0.0021 to 0.024 m. That, during the movement of oil in a horizontal pipe, the head loss with a sudden expansion is 1.33 times greater than that of a sudden narrowing.

Transport phenomena in an agitated vessel with an eccentrically located impeller

2011 ◽  
Vol 65 (2) ◽  
Author(s):  
Magdalena Cudak ◽  
Joanna Karcz ◽  
Anna Kiełbus-Rąpała
Keyword(s):  
Reynolds Number ◽  
Shear Rate ◽  
Friction Coefficient ◽  
Transport Phenomena ◽  
Turbulent Regime ◽  
Cylindrical Wall ◽  
Flow Measurements ◽  
Rushton Turbine ◽  
Agitated Vessel ◽  
Inner Diameter

AbstractThe paper presents results of an experimental analysis of the transport phenomena at the vicinity of the wall of an unbaffled agitated vessel with an eccentrically located impeller. Distributions of the transport coefficients were experimentally studied using an electrochemical method within the turbulent regime of the Newtonian liquid flow. Measurements were carried out in an agitated vessel with the inner diameter T = 0.3 m. Liquid height in the vessel was equal to the inner diameter, H = T. The agitated vessel was equipped with a Rushton or a Smith turbine or an A 315 impeller. Eccentricity of the impeller shaft was varied from 0 to 0.53. Local values of the dimensionless shear rate, shear stress, dynamic velocity and friction coefficient were integrated numerically for the whole surface area of the cylindrical wall of the vessel. Averaged values of these quantities were correlated with the impeller eccentricity and modified Reynolds number. The proposed Eqs. (5)–(8), with the coefficients given in Table 2, have no equivalent in open literature concerning this subject. Distributions of the shear rate, γ/n, and friction coefficient, f, at the vicinity of the cylindrical wall of the unbaffled vessel equipped with eccentric Rushton or Smith turbine or A 315 impeller are very uneven and they depend significantly on the impeller eccentricity, e/R. Maximum local values of these variables are located on the wall section closest to the impeller blades. From among the tested impellers, the greatest effects of the impeller eccentricity, e/R, and the liquid turbulence (described by the modified Reynolds number Re P,M) on the averaged dimensionless shear rate (γ/n)m and friction coefficient, f m, are found for the radial-flow Rushton turbine located eccentrically in an unbaffled agitated vessel.

Flow behaviour of bentonite-water suspensions in a horizontal pipe

1973 ◽  
Vol 8 (3-4) ◽  
pp. 193-195 ◽  
Author(s):  
P.V. Sharma ◽  
R. Nagarajan ◽  
G.S. Davies
Keyword(s):  
Flow Behaviour ◽  
Horizontal Pipe ◽  
Water Suspensions

scholarly journals Counter Current Flow Limitation of Gas-Liquid Two-Phase Flow in Nearly Horizontal Pipe

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sigit Prayitno ◽  
R. A. Santoso ◽  
Deendarlianto ◽  
Thomas Höhne ◽  
Dirk Lucas
Keyword(s):  
Inclination Angle ◽  
Current Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Limitation ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Air Inlet ◽  
Inner Diameter ◽  
Counter Current

Experimental work about counter current two-phase flow of air and gas in nearly horizontal pipe has been performed. The work was performed in a 1.1 m long circular transparent acrylic pipe with 50 mm inner diameter, in two inclination angle settings (20° and 10° from horizontal). The smooth liquid and air inlet was used. Porous liquid inlet and a nozzle connected with calm section were used as liquid and gas inlet. The effect of liquid properties is examined by using five different working fluids (Water, two different concentration of butanol and glycerin aqua solutions). As for results. (1) CCFL causes a drastic change in the delivered liquid to the lower plenum. (2) The effect of inclination angle is significantly observed. The flooding gas superficial velocity decreases with inclination angle. (3) The liquid viscosity affects the flooding phenomena.

Turbulent Flow Behaviour in a Pipe Fully Submerged in a Hot Fluid

2017 ◽  
Author(s):  
Benjamin Steen ◽  
Kamran Siddiqui
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Vertical Plane ◽  
Flow Behaviour ◽  
Turbulent Regime ◽  
Fluid Temperature ◽  
Cross Sectional ◽  
Turbulence Transition ◽  
Flow Mixing

We report on an experimental study conducted to investigate the flow behaviour in a heat exchanger pipe submerged in a hot stagnant fluid. Particle Image Velocimetry (PIV) was used to measure the two-dimensional velocity field in the mid-vertical plane of the tube. Fluid temperatures in the cross-sectional plane were also measured using thermocouples. The mode of heat transfer into the pipe was mixed convection where both inertia and buoyancy contributed to the convection. The results show that when the contribution of buoyancy-driven flow (natural convection) was smaller than that of the inertia-driven flow (forced convection), in an originally turbulent flow, the shear-induced turbulence dominated the flow and the turbulent velocity profile was not influenced by the heat input. In an originally laminar flow, the role of buoyancy was primarily limited to the initiation of instabilities in the laminar flow to trigger the turbulence transition. The temperature profiles indicate the presence of stably stratified layer inside the pipe in originally laminar flow regime that suppressed the heat transfer rate. In originally turbulent regime, the fluid temperature field was nearly uniform indicating efficient flow mixing.

scholarly journals Experimental study of flow around polygonal cylinders

2016 ◽  
Vol 812 ◽  
pp. 251-278 ◽  
Author(s):  
S. J. Xu ◽  
W. G. Zhang ◽  
L. Gan ◽  
M. G. Li ◽  
Y. Zhou
Keyword(s):  
Reynolds Number ◽  
Lift Coefficient ◽  
Separation Point ◽  
Flow Visualisation ◽  
Outer Diameter ◽  
Roughness Elements ◽  
Image Velocimetry ◽  
Inner Diameter ◽  
The Difference ◽  
The Relationship

The wake of polygonal cylinders with side number $N=2\sim \infty$ is systematically studied based on fluid force, hot-wire, particle image velocimetry and flow visualisation measurements. Each cylinder is examined for two orientations, with a flat surface or a corner leading and facing normally to the free stream. The Reynolds number $Re$ is $1.0\times 10^{4}\sim 1.0\times 10^{5}$, based on the longitudinally projected cylinder width. The time-averaged drag coefficient $C_{D}$ and fluctuating lift coefficient on these cylinders are documented, along with the characteristic properties including the Strouhal number $St$, flow separation point and angle $\unicode[STIX]{x1D703}_{s}$, wake width and critical Reynolds number $Re_{c}$ at which the transition from laminar to turbulent flow occurs. It is found that once $N$ exceeds 12, $Re_{c}$ depends on the difference between the inner diameter (tangent to the faces) and the outer diameter (connecting corners) of a polygon, the relationship being approximately given by the dependence of $Re_{c}$ on the height of the roughness elements for a circular cylinder. It is further found that $C_{D}$ versus $\unicode[STIX]{x1D709}$ or $St$ versus $\unicode[STIX]{x1D709}$ for all the tested cases collapse onto a single curve, where the angle $\unicode[STIX]{x1D709}$ is the corrected $\unicode[STIX]{x1D703}_{s}$ associated with the laterally widest point of the polygon and the separation point. Finally, the empirical correlation between $C_{D}$ and $St$ is discussed.

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